It really depends on how anal you are about the paint.
My X5 is a 2008 with sapphire black paint and it's been in a garage for maybe 48 hours in that entire time.
That being said the paint is in great condition and it appears to me that it's very tough, as i've been using chamois and costco microfiber towels to dry it and as far as I can see, there's no scratching. (at least to the naked eye, i'm sure if Phil examined it there would be some very fine scratches).
If you don't want to use towels you can always use a blower -
Air Force Master Blaster Car Dryer