Alan it is up to you and I am not trying to start 'stuff' with you.
The Code is to promote safety and I feel that circuits from two separate services in the same raceway is creating an unnecessary hazardous condition.
You may feel
it is hazardous condition but the NEC does not, you are going out on your own here.
Using 215.5 as a form of extortion to get what you want is hardly fair to ECs that are following the NEC.
Consider this, the NEC does not prohibit conductors from optional standby systems from occupying the same raceways as utility power. Mixing conductors from separate sources is common.
If you feel it is a hazard you should put in a proposal.
Don't let the fact that you have been doing it 25 years make you forget your job is not to make code but enforce existing code.