I don't think that this is good practice, but I can see that it wouldn't be as horrible as some make it out to be.
Nobody would run four mismatched tires on anything but a beater and almost every beater still on the road these days is FWD.
Under hard cornering, the outside front tire rules and the rest are pretty much just along for the ride.
Therefore, I don't think that differences between the tires matter all that much.
It'll always be the outside front that determines the car's behavoir with the rest just following along.
It also requires serious work to get a FWD car to try to swap ends on you.
Give it a try sometime on a wet road where you have plenty of room for recovery.
Bet you can't make it happen without resorting to tweaking the parking brake.
Nobody would run four mismatched tires on anything but a beater and almost every beater still on the road these days is FWD.
Under hard cornering, the outside front tire rules and the rest are pretty much just along for the ride.
Therefore, I don't think that differences between the tires matter all that much.
It'll always be the outside front that determines the car's behavoir with the rest just following along.
It also requires serious work to get a FWD car to try to swap ends on you.
Give it a try sometime on a wet road where you have plenty of room for recovery.
Bet you can't make it happen without resorting to tweaking the parking brake.