It's not a loophole or predatory, it's just something the people doing these one-off job knowingly agreed to. I myself certainly agreed to it years back each and every time I accepted another order. The key was to not agree to orders that don't make any fucking sense. It was all optional.
I don't know how we could ever regulate away the issue of people who decide not to act in their own best interest. Probably best to focus on education or something?
Lol the older brother is just an idiot. He isn't 'forced' to do anything at all. The business arrangement makes no sense unless the little brother being the salesman adds value somehow.
I am an older brother and I assure you if long ago my younger brother was like "hey you need to shovel the neighbors driveway for $3'' I'd be like "lol, no, go give that nice man back his money. If you want to be my salesman, I need the guarantee of $10 in my pocket minimum. If you can find a guy who pays $11, by all means keep the dollar. Oh, also I get any tips provided after the job."
Do you actually think any older brother is going to just keep shoveling driveways for $3 when he thinks he deserves $10?