This is Tactics and Training and concerns of capacity constantly arise. The common wisdom is that 5-7 shot capacity is plenty...until it isn't.
So, I'd never fault a man who wanted to CCW a Glock 17, two spare magazines and a Glock 26 BUG, or anything else. I guess a MAC 10, UZI, etc is about the upper limit for concelability. I'll never forget when Regan got shot and the Secret Service Man produced an UZI out of seemingly thin air.
Most of us, including most LEOs will never draw on someone IRL. Our CCWs are like fire insurance, in that its only wise to have it, but we hope to never need it. Its strictly up to the individual what level of insurance