Those people who have replied negatively to this thread -
If they aren't doing it illegaly then why should it matter that someone is telling the revenue - they'll be fine.
If they haven't registered then it is ILLEGAL. Its your choice whether you tell or not, but all those who have said they definately wouldn't... where do you draw the line? Would you ''snitch'' if you saw someone being raped or is that underhand too :
Most people wouldn't take the trouble, but the reason people who are on benefits can underprice is BECAUSE THEY'RE NOT PAYING TAX. We have to earn 22% more (or whatever) because we are paying our tax. So it is completly understandable that people DO shop people they think may be evading.
I don't think I'd bother personally unless they really peed me off but people shouldn't bmock others for doing what is after all ''the right thing to do''