The first phone I had to Google Wallet on was my Verizon Galaxy Nexus (when wallet first came out and WAS stored completely on the secure element) then on my Sprint Galaxy S III and now on my Sprint Galaxy Note II.
I have never once reset Google Wallet on any of my phones before flashing a new ROM, and never have had a problem.
So not resetting Google Wallet before flashing a new ROM does not guarantee a secure element warning.
This debate has been going on since Google Wallet first came out on whether or not it helps to reset the app prior to wiping your phone and flashing a new ROM.
There really is no proof either way works better. I have seen people post that they have received the secure element warning when doing it both ways.
On a different note should this thread really be in the development section?
Sent from my SPH-L900 using xda app-developers app