well it happens everywhere.. we have basically almost every day one of our planes dinged up by a water truck, baggage trolly, catering truck, stairs, etc..
once someone drove a bagage trolly under one of our CRJs and it got stuck so hard, the tail had to be jacked up to et it out.. stuff like that
But you need to consider it's not only Pilots having fatigue.. also ground crews are affected by night time shifts and lots of work (with not too good a payment usually)
Cheers
Mb