I wasn't going to post on this thread because there is a similar one running elsewhere.
So noseall and maybe Dex think it racist to refuse to work for a group of people that have a habit of knocking you at the end of a job.
My own experience:
Most of my customers over the last 30 something years have been white British. Most of them have paid up at the end of the job, some have delayed payment for reasons best known to themselves. But I can honestly say that I can't think of a single one that refused to pay or wanted to re-negotiate the price after completion.
Amongst the small number that weren't White British. I have had, I can't pay, won't pay, and now it's time for a little re-negotiation. They have all paid so perhaps it was just their culture to try it on.
It's far better to avoid a problem than having deal with it once you've worked your balls off. More so when you saw it coming. I won't work for them, no exceptions. Anyway, they wouldn't want a racist working for them either I guess. A few years back I would have just been the bloke that wanted paying for work done.