Even though this may be against your personal picture of BB-refs as totally incompetent, I'd like to suggest rules that make the refs a bit more consistent:
There are 2 ref counters. Each is above the "6" square in the TD track.
This signifies the roll needed to spot a foul by that team.
The 2 counters are moved independantly of eachother.
Now, whenever a team fouls, make a spot roll as normal.
If the spot succeeds, the player is sent off as normal - and that's it.
If the spot roll fails, then move the reff counter for the fouling team one square to the left, (i.e. first time it is moved to the "5" square).
The counter can only move left, and is not reset at half time.
This ensures that no team gets off too easy, or gets hit too hard.
How do you like this?
Martin

PS - for those of you who love "rationales": The logic behind this is that when a spot roll fails, the ref did in fact see the foul, but didn't consider it too bad. However, it will increase the chance of him having "had enough" next time the team fouls.