Too bad this isn't true for CDMA-based providers. It'd be nice if you could simply enter the ESN for any CDMA phone into your provider's website and BAM... service.
you actually can in ,ost cases if you are willing to do a bit of 'flashing' to get the setting right.
while sprint does not allow flashed phones. verizon, cricket and metro always have. so while it is extremely rare for people to put spirnt phones on verizon it is entirely possible. flashing is common on cricket and metropcs.