It's monumentally stupid to use a weapon to commit any crime.  It takes a special class of stupidity to do so with a BB gun.

Larry Keane
Legal counsel to the National Shooting Sports Foundation in Newtown, Conn.
USA Today January 15, 2006
[For the clueless I'll spell this out.  After all, with a weapon you would think you would get better victim compliance.  The disadvantages are:

1. In many jurisdictions using a weapons will mean you serve more time in jail when you get caught.
2. Committing a crime using something that looks like gun is the universal sign for "shoot me" (masked men with guns are always targets).
3. Using a BB gun means you have all the disadvantages of using a gun without the advantage of real force multiplier.

--Joe]