I know multiple people that still have active 3G phones on Sprint...
you're right:
“We are proceeding as planned with the orderly shutdown of our CDMA network beginning on March 31. As part of our shutdown process, we are migrating customers in some areas over the following 60 days to ensure they are supported and not left without connectivity, and the network will be completely turned off by no later than May 31.”
So, earlier reports were accurate in that the final cut-off is May 31. However, the transition begins as earlier stated on March 31, so it would appear that some will see the ramifications of the extension and others will not.