I had a similar thing happen to me with
Buena Vista Scooters at one of the Disney resorts in the past year or two - I just can't remember which trip but they called me to say my scooter wasn't returned and I freaked out. Like you - I dropped it at the Bell and the guy just took it and said no you don't need to sign the log sheet (I think this was Coronado Springs). BV's reaction tho was just to tell me and they never said anything about charging me extra days for the scooter. I did have the insurance but I it does NOT cover stolen scooters - I just looked at it and it only covers damage. I'm not sure any insurance covers stolen ones.
From now on I not only sign the book
I take a photo of it and a photo of me returning the darn thing. I agree with others that I think they give it to someone else (maybe someone who had a scooter problem or whatever - so that's why it doesn't show up back to them for days). I'll still rent from BV but
does any scooter company have insurance that covers stolen scooters?