DONE: Provide a way to disable p4 (2016.1 patch 1) command auto-login feature
This was provided in a 2016.1 patch, per Sven's comment below. Thanks!
Per the release notes:
#1243015 (Bug #79913) * ** The p4 command line, run interactively, will now prompt for login if a command that requires authentication is run when the ...