Depends.. Active, as in 'keeping an account from being closed due to lack of activity'?
Maybe a play every few weeks would be o.k., or maybe even once a month at the least, depending on how much money is in the account.
Active, as in "account must remain active for 30 days to recieve bonus"? I would say at least 2 or 3 wagers a week. At the absolute minimum, i would say a play a week.
Now, should a player be allowed to roll an account ove the required amount , then let the account sit idle for 28/29 days , then expect that the account has been sufficiently "Active"?
I would say hell no, and send the dipshits name to every other book as a heads up..
Just my opinion of course.