Hi
Some travelers are reporting that upon picking up their car rental they use the key fob, but on return of the car they are charged fees for damage / repair to the door lock.
Check the car lock when first picking up the car.
Happy travels

Could it be that someone other than the renters tried to force the lock at some point during their trip?

On the other hand, a car with a broken lock and a key fob could be an ongoing profit center for an unscrupulous rental location that never repairs it. Excellent advice from the OP.

We have rented perhaps 65-70 cars in Europe since 1987. The cars we've rented have been damaged twice, and we "reported" it to the return office.
- Last year when someone hit our car while it was parked somewhere. MC paid for the damages after a lot of "back & forth"
- In 2014 when someone hit our car while it was parked in a parking lot. Europcar must have lost all the papers, because we never received a "final invoice" with all the normal environment, train station pickup charges - and damage charges.

We have "dented" the car perhaps 3-4 times ourselves, and did what we could to cover/repair what was damaged. And we did not report it upon return. We were not charged for any repairs.

So - .over 65-70 rentals of usually 4 weeks per rental, we have only received 1 invoice that included charges for damages.

Stu Dudley