So not all. And if it isn't a principle, how much is too much?
I have no idea. Maybe you have an idea of how much & will share it, so we can think more about it. Of course there are some rich people who are greedy and companies who know all the dodges but that's different to someone who finds it hard to make ends meet and welcomes a little extra cash.
Like wigginhall, I would not snitch on them anyway. The idea of snooping into the private business of others is abhorrent to me, I'm happy to leave it to income tax officials.
Doesn't apply to me, eg I don't design websites, do hair, fix cars or washing machines & don't need extra income. I'm paid a salary from which tax is deducted, from that point of view life is simple for which I'm grateful. However I'm well aware it's less simple for others.