Several years ago, DD's ex boyfriend got a part-time job. He and his father were thrilled that he was paid under the table. Until I pointed out that :
1) if an accident happened, he would not be insured by his employer or the work safety board, even if he was disabled,
2) he would not have access to unemployment insurance,
3) if there was any problem at work, he had no recourse, because he was not an employee,
4) no social benefits,
5) if the job site was inspected by the work board, he and his employer would be in major trouble (it was in some construction related field, very regulated).
I don't remember if he took it or not, but I was not impressed with the father.