My husband is a tradesman. He's not a thief or unreliable or irresponsible. He's met many unreasonable and unreliable customers though... including those who boast to their friends that they "never pay a tradesman in full" even if the work has been completed to their satisfaction.
There definitely are some dodgy builders about, like there are dodgy cleaners, window cleaners, mechanics, lawyers, hairdressers, house sitters, dog walkers, child minders, policemen, doctors etc etc.
Being a tradesman does not make someone a thief, undesirable or irresponsible like some people on here seem to think.
Do your research and get recommendations and references. Ask to see insurance etc.
Also. Remember that the tradesman is trusting you to pay him at the end of the job. They're literally dependent on you not being untrustworthy so that they can pay themselves and feed their families. This means they're quite unlikely to rob your house.
A lot of customers seem to forget that the trust goes both ways.