Obviously, you can charge them at rates lower than 1C, just not higher. 1C is the Upper limit. There is no lower limit. It won't explode from charging at too low an amperage.

I did notice in one of the RC Driver magazines that there was an ad for the 2S 7.4v 4800mah Lipo (The silver one - Orion maybe?) that came with or could come with a Scorpion 2S charger. In the ad, it said "be back on the track in 20 minutes"

Correct me if I am wrong, but charging a 4800 mah battery at 1c (4.8 amps) should take 1 hour to charge, right?

That would mean that they are charging that battery at 3C!!!! Hmmmmmmm.