Francisco Canseco took a stand when a TSA agent tried to give him an enhanced pat-down last spring.

Canseco, who happens to also be a Texas congressman, objected to the agent’s forceful frisking, and a few days later, to being singled out for a secondary screening. Police had to be called in that incident.

A report published by the San Antonio Express-News last week, which retrieved an incident report under the Freedom of Information Act, paints a complex picture of Rep. Canseco’s confrontation: A legislator who had already taken a public stand on the agency’s effectiveness — or lack thereof — and airport agents who may have wanted to show the congressman who’s in charge.

But it also raises a bigger question: When do you say “enough” to the TSA?

After I wrote about the things you shouldn’t say to the TSA, I sustained a little friendly fire from agency critics, who believe you should always give agents a piece of your mind.

I understand where they’re coming from, and I agree with them, in principle; you shouldn’t ever feel like you have to remain silent. (And yes, I was horrified that a majority of those polled said they were afraid to speak up. Come on, people!)

Sure, there are times when you want to skirt the issue. For example, when you’re running late for your flight, you don’t want to get into an argument with an agent about the Fourth Amendment. The luxury of a debate is something you forfeit for sleeping in that morning. Likewise, you probably don’t want to find out how photogenic your screener thinks he is when your flight is already boarding. Keep the camera in your luggage, keep your head down, and be done with the screening.

Here are the times you should take a stand.

When you’re uncomfortable with the screening process. TSA’s screening process has evolved from a common-sense approach to checking passengers a decade ago to the multimedia circus we’re subjected to today. One thing hasn’t changed: The little voice inside of you that says, “That’s it. I’m no longer comfortable with what’s happening.” It’s the moral compass that always points to “right”. No federal agency can take that from you, or reset it, or force you to ignore it.

I may not agree with every position Rep. Canseco has taken, and I wasn’t there when he took a stand against his enhanced pat-down (see video, above). Did he want to create a controversy? Maybe. But I have no doubt that many TSA agents, given the chance to give a critic a little payback, wouldn’t hesitate. I also have no doubt that he was made to feel uncomfortable. He had the right, and the obligation, to say something.

When you’re uncomfortable with how someone you’re traveling with is being screened. If you’re a parent flying with your children or an elderly relative, you have an obligation to monitor a TSA screening. Even though the TSA has special procedures for children and seniors, agents still have a lot of discretion in how they can screen your dependents. It’s still possible for them to cross a line.

It isn’t just that an overzealous pat-down can traumatize the most vulnerable among us, potentially leaving them with lifelong scars. It’s that every time we let them take our children into a private screening area and reach under their belts and stroke their limbs, we are effectively giving them a license to continue violating our basic constitutional rights. You have to speak up.

When you see something you think may be illegal. TSA agents have a well-deserved reputation for stealing from luggage. Screeners are not above the law, their blue uniforms and shiny badges notwithstanding. If you see something, say something.

When you believe you’re being punished. If the screening process lasts too long — say, you’re you’re stuck in a glass enclosure for almost an hour, like this woman — then you have to take a stand. Agents who are questioned may use some of their “discretion” to subject you to anything from a lengthy screening to a long wait in an enclosed area. That’s just wrong, and you need to speak up when it happens.

When the screeners shouldn’t be there. TSA airport screeners who find themselves in a subway, train station or at an NFL game, should be questioned no matter what they do. The infamous VIPR program is a troubling breach of the TSA’s understood mandate, and agents who try to stop and question you have virtually no jurisdiction, legally speaking.

If you see uniformed TSA agents outside the airport, and they’re not off-duty, feel free to assume they’re up to no good. Actually, you can probably make that assumption even if they are off duty. If one of them tries to force you through a magnetometer or rifles through your belongings, tell them you do not consent to a search. They will probably have no choice but to let you walk away.

This is by no means an exhaustive list of times when you should take a stand against a TSA screening procedure. You will have your own list somewhere, maybe not fully articulated, but you’ll know when to say, “stop.”

Don’t be afraid to.

When you do, remember: The agents screening you don’t like confrontations any more than you do and they respond well to politeness. The only fault I can find with Rep. Canseco’s confrontation is that he swatted the agent away, when he could have simply stepped back.

Raising your voice, hitting an agent or threatening one of these federal employees may feel good in the moment, but it is almost totally unproductive when it comes to ending the TSA’s questionable screening practices.

There are more of us than there are of them, and when we politely but firmly refuse to be treated like criminals, we will win.