Ammo scarcity is hitting even the police. Big departments probably have a good contract that covers their yearly need, but some smaller departments might be out of luck.
This article is from Richmond, CA. Richmond PD is using airsoft guns (and SIRT training guns) for practice instead of live ammunition. I don't know what they will accomplish with no colored muzzle, but this might be better than no training at all.
Notice the 1*(1 ass to risk) on the slide of real gun around 0:50