If we had a listing of the people we hacked we would not hit them more than once in a 12 hr period. I have had difficulty in knowing who I hack in the last 12 hrs. I mistakenly hit someone twice.

agreed... or (something i mentioned a while back)... some sort of indicator showing whether or not we're eligible to get a certain badge at the moment
(like... having the badge appear on the attack, raid, hack, or invade buttons if we're eligible)

+1, I'm hacking people twice within 12 hours at least once a day, and I feel bad when I do it.

This was suggested before and i agree with it 100%

+1
Or maybe a new row in the BT showing the various badges you obtained from that player within 24 hours (using the badge images to keep it compact).

one week for the green...