Your best bet is to set a password to prevent the wallet from staking.

This issue is why I added:

mint=0   to the configfile
setmint false to the command line / console

and a checkbox to the user interface so that it was wholly opt in.

In fact -- this is exactly how SNF's primary GiveCoin wallets are online but not staking -- so long as the main chain is producing enough POS blocks we're keeping the inflation rate low, staking only in our donation wallet at the moment.

-dvd