You can argue that customs and border controls should be more liberal in general. I'd agree and, I think a lot of people would. But there is an element of you know what the risk you're taking is.
The police are often overzealous and unreasonably heavy-handed towards women where they suspect sex-work (and by extension, drugs, as the two are often connected). This is bad and the way they treated Mutiny sounds completely unnecessary and humiliating, that is not in dispute.
Work is still legally work even if you don't make any money off of it. Even if your work doesn't cover your bills, it's still work. Now, you can argue that working conditions are shit for low paid people and need to be addressed. Again, I'd agree, and again, a lot of people would.
Nothing you say is per se unreasonable. But the system is what it is, and right now you have to abide by the rules, fair or not, or you get punished. What's insidious here is that there is someone who is deliberately targeting session wrestlers who are travelling - i.e. there's no way Mutiny here, or Lia in the UK, get caught without someone tipping customs off. This is the key point - our little community isn't going to change the customs & immigration system, sadly, so what we need to focus on is if there is anything we can do about the asshole who has decided he wants to make these womens' lives hell by blocking them from customers and having them barred from countries.
Railing against the injustice in the over-arching system is understandable, perhaps even correct, but it doesn't fix the problem in the here-and-now (and pressure groups on the issue are unlikely to want to make a session wrestler into a banner case) for the sessioners. The system can be worked around, but one individual is preventing that work-around from happening.