[Boeing Guy]

Roy I fully understand your point, I am also in a serivce industry.

On my walk round of the aircraft, I will open a hold if it is shut and have a look inside, check the wheel wells for anything out of the ordinary. The cabin crew always check the interior of the aircraft, storage bins, toilets etc for anything.

I personally don't see a problem here, I would have thought in these troubled times that a Bus driver would want to have a quick check of his Bus before a fresh run to make sure there is no security threat, (bomb!). I know I would.
BG

ps.On a small note, in the old days (90's), Drivers for Pilkingtons Buses, used to get paid for sweeping and mopping their buses out after the shift.