I just had to post this because you may run into the same problem if you are fortunate enough (!) to live in a place where you have winter tires and summer tires and someone does not do his job properly taking the wheels off.
Radial tires should not be rotated corner to corner on your car, the way bias ply tires were rotated back in the day. Many car owners report unusual pulling when radials get moved around after having been in one location for most of their miles. At most, swap backs and fronts on the same side of the car, or else just leave them be.
We bought winter tires and rims for my wife's car last fall, and when the dealer installed them he did not mark the location of each wheel in the summer set that he was taking off. I was re-installing the summer wheels and tires for my wife's car on the weekend, and had to figure out where they belonged just by looking at the tires.
Hard? Uh uh. Wild guesses? Nope.
Front vs back: It is a front wheel drive vehicle, meaning more weight and more potential slippage wear on the front tires. So, take the two tires with slightly less tread left, and figure they are the fronts.
Left vs right: Face it, the purpose of a curb is to scuff your tires. Curbs mostly show up on the passenger side of the vehicle. Passenger side tires have scuffed sidewalls.
Double check: Front tire gets scuffed more often than rear tire. This checked out just fine.