do you have any facts to back up your claim that spacers are in fact dangerous?
no he doesn't. but he knows everything.
as is the case with most product complaints, failures are most often caused by user error. in the case of wheel spacers, they're usually installed incorrectly or improperly torqued or used on the wrong vehicle.
and for the record, what we in this thread have been calling wheel spacers are in fact wheel adapters; though we use them to space the wheel.
true wheel spacers are thin shims that fit between the hub and the wheel. they're only meant to offset the wheel by millimeters. these are arguably unsafe, but again it's usually a direct result of improper use/installation.