I am sure that you could keep them on your car and I am sure you will be able to get to your destination. The fun will happen when you need to do an evasive maneuver because of someone else driving in the snow on summer tires looses control. haha. in 2002, I had summer 20" on my E53 and it took one OH $4!T moment to convince myself that spending the money on a dedicated winter set for all my cars/suv's was well worth the $$$. Besides in the long run you almost/do break even. I know I broke even on my 540, E53 and SL500 when it came to the cost of running summer/winter setups

__________________
2012 X5 50i ZAP(2VA, 336, 465), ZTP, ZPP, ZPS(6VC), ZCW, ZRC, 322, 4UB, 4NC, 610
2011 ///M3 Silverstone II
2011 X5 50i(lemon)
-- SOLD --
08 550 Msport
07 X5 4.8I sport
04 545i sport
02 4.4i sport
01 540I M/sport
00 SL500
97 SL500