eetsoop,
a motorized wheelchair is not an ECV. There is a big difference. There are many models of both manual and motorized wheelchairs. Not one is standarized. One thing that can tip you off it is not an ECV but is a motorized wheelchair doesn't have handbars in front like an ECV. It has a controller on either the right or left armrest unless it has a specialized controller such as one in the headrest or a sip and blow controller. No basket in front either. A motorized wheelchair can be tieddown on a ride if the guest chooses to remain in it. I usually do not and prefer to transfer with my sticks. As I have said before, if I could use a manual chair I would.
It is not a safety issue as you claim but a laziness issue on the part of the workers who do not care to ask the users about where to place tiedowns on the particular modeel in use. Trust me, when you use these mobility devices day in and day out you know better than some theme park worker where to placec tiedowns and what is safe and feasible and what is not.