Absolutely, a French friend of mine and his Thai wife have a scooter rental shop, in the past he had 2 rented to Thais and never brought back, police weren't interested, this is in Chiang Mai. Never rented to Thais since then.
The 1095 Chiang Mai to Pai is quite a 'tastey' road for uninitiated, over 700 corners, around 130kms. Weather can change very quickly before reaching the downward section, great road for the big bike. It's claimed alot of lives over the years especially young people on scooter type bikes.