Never besides one exception The only situation that i might consider is at a grocery warehouse where they can take upwards of 8-12 hours to unload you. Tell the lumper he has a $20 bill waiting on him if he gets me out of here fast.
Problem is the lumper may unload you in less than half an hour, you still have to wait half a day for paperwork.
When I ran reefer I used to get sent to the worst customer on occasion (Americold in Covington PA), was always there for 8-10 hours and would always miss my next delivery. One time I went I slipped $10 into the trailer with a note that said "finish me in 2 hours and I'll give you another $10". I was finished in 3 hours and I made my next two deliveries on time. Next time I went I did the same thing but sat for 9 hours and never tipped a lumper ever again. Short answer is no, don't tip the lumper.
