Question to all the police downvoting this, can you explain why? I truly don't see how this can be a negative at all, unless you just want an easy "win". If a bank was being robbed by 3 people, and 9 police officers are allowed to attend the scene, it allows for extended roleplay, as the robbers aren't completely overrun. It makes it more enjoyable for the officers, they're actually getting involved and aren't just in the background, the chase would also be extended. In terms of the 'balance' towards crims, it makes it so there's a genuine likelihood of escape and better RP. It's literally a win win for both parties involved, think of it from a neutral POV and not in the eyes of police.
Use your common sense mate, if, for example, a gang of 10 people rob a bank, obviously that would increase the risk factor and change the amount of officers needed to respond