I'm pretty sure that I'm not the only one gassing my non-flex fuel vehicle with E85.
I actually had to wait to gas up tank #6. A guy was gassing up his 2000 Linclon Town Car. He put in 13 gallons. That's nowhere near the capacity of a Town Car, and I'm pretty sure that they're not flex fuel.
When I filled up my wife's van, the pump indicated that the last customer put in 2.5 gallons.
After I used it, the next customer was a late model Chevy Impala. It did not have a flex fuel badge, so I'm pretty sure that it was a non-flex fuel model.