there are probably a bunch of different opinions on this subject. when i hire a new person and i go over all the ground rules, one thing i always tell them is to never accept a cash tip. i've also had customers ask me if it's ok to give a cash tip to my workers and i always tell them that i would prefer if they did not. if they insist, i always suggest coffee or something to eat is more than enough. i have one customer who, for the past 3 years, bakes an apple pie for me and for one of my employees every fall. this job is 100% about getting recommendations and i don't want to compromise that possibility. my men get paid well and if there's ever anything extra made on a job, i'll tip them myself or give them some other kind of bonus.
i know alot of you will disagree with me but that's my policy and my opinion.
Be sure to ask the owner of the company if tipping is acceptable. As for tipping the foreman, if he is working as hard as the rest of the crew, his tip should be equal. Chances are, he's getting paid more, but it could create hard feelings to tip him less.
The exception is if the foreman is also the owner: as a general rule, you never tip the owner of any company, only employees.