I just wasted a half hour tapping in a long reply that my PDA 'ate'.
Short anwer: your 600mah Lithium Polymer in relatively good condition can dump three amps minimum into a circuit for a few minutes... or until a wire melts... Yes, it will set off a blasting cap.
I'm enough interested in this topic to write up a long article for my blog on it. Maybe get something posted there tonight, but I gotta get some sleep now.... Ive been up for 20 hours.
I'd be real interested in some evidence that the cheapest of the cheap bottom-line cell handsets are sold with lithium batteries.