I don't know if there is an official rule requiring 3 or 4 hours of minimum paid work, but at my store sometimes a 2- or 3-hour shift slips through the cracks (usually when someone was split between work centers and removed from one but not the other). ETL-HR told me: 3 hours or less and you are not required to come in to work. Just tell an ETL you have a shift of that length and they will remove you from the schedule, or extend you if you're interested and hours are available. There aren't many things my store does right, but at least they got that one.
To answer the original post: No way I'd ever work a 3-hour shift; I can find ways to be useful and extend after my normal shifts if I need hours, and during holiday season if we get into enough trouble for overtime to come up I'll stay and work 12 to 15 hours if I can. 3 hours isn't going to happen, I'd rather take a nap. 😉