Do the roasties on Chaturbate pay their taxes?
Probably not, even though it's theoretically traceable due to money trails left over in cyberspace.
Generally, 'underground economy jobs' which prostitution includes, do not end up becoming income taxed, due to the inability of government to consistently and effectively infiltrate and prove what transpires.
As far as how you would report them...it will vary from country to country depending on factors such as the political environment. For instance, backpage would probably still be up had Hillary won instead of Trump. Part of the reason backpage went down, is "revenge" for what Stormy Daniels and the sex worker coalition did.
If you are earnest, you would first need to have evidence of what the prostitute is being paid, such as through screenshots, and then to get hold of the relevant tax entity (For instance, in the US this would be the IRS) of the country in which said prostitute lives and works.
The fraud hotline for the IRS (last I checked) is: 1-800-829-0433
