This command will hold on the network for 7 days. After that the command is dropped. This situation is out of your hands, you can't sit and wait for weeks to see if the command works. While you're waiting this user cannot use a BB, the longer you wait the longer the user waits.
Also, do you enforce password protection? If so, they will have to get the correct password to gain access to the BB and after 10 attempts it will erase itself anyways.
If you don't enforce it you might want to now, live and learn I guess.