As I have said many times before I don't particularly care, as if I were paid cash in hand I wouldn't declare as it, as wouldn't most people (despite what they say! ) and we know that many other workers who take cash in hand don't declare it.
However what I do strongly object to is them taking us for idiots and sincerely expecting us to believe them when they stamp their feet and insist they pay tax. Of course they aren't going to publicly admit they don't.
Strawberry may be an honourable exception, I don't know and never will, but if she is I can tell you without any shadow of doubt that she will be in a tiny minority.
There are other reasons, other than being "honourable", for putting a reasonable amount of your earnings through tax system, even if a lot of your earnings are in cash.
If you want to do things like buy a house, pay monthly mortgage, etc things can get difficult if you constantly produce wads of cash out of thin air. Money laundering regs always make it possible that "suspicious" cash deposits will be highlighted to the "authorities".
I don't know likelihood of getting caught out (probably pretty low given how stretched IRS is).. but I do know consequences if you do get caught out can be life wrecking. (A good friend of my fathers had a darn good business that took a lot of cash completely destroyed…after years of making stupidly low tax returns when a young bright tax inspector checked his books.)
Certainly… I think anybody who's main income is from escorting (rather than it being a useful side income).. would be well advised to declare majority of earnings for tax. You know… probably rather similar to way taxi drivers, waiters, etc put some of their earnings through tax system, and omit others.