Putting winter tyres on front and summers rear is stupid and dangerous imho.
Insurance companies will hold your negligent if you are in an accident.
Mixes treads front and rear can have a massive impact to some cars and hardly notice on others.
I always keep all 4 matched.
I have had too many BMWs where it becomes twicthy and the traction control flicks on and off constantly with different tyres front and rear. The difference is easy to spot when you get to know it.
Who would do such a thing?
They're out there, and driving on a road near you.
Search for the post on pistonheads where the driver said he aquaplaned on the M25 "I was only doing 60mph, went to overtake and the next thing I know I was facing backwards and spinning across all 4 lanes and nothing I could do."
Turns out he had winters on the front, hadn't changed the rears yet as they still had "plenty of life left in them."
****!