I've used three strategies:
1) Just go out there and plug it in at the right time before I go
2) Use an el cheapo timer when I know ahead of time when I'm gonna go (work commute)
3) Have the outside outlet on an indoor switch
Oh yeah: rows upon rows of idling SUVs almost give me a migraine, just from the mass stupidity of it all.
I think autostarts should be outlawed.