You’re assuming you’ll still have the employee if you refuse.
The point is that once you have no leverage over employees (because their livelihood doesn’t depend on the job), you cannot establish what is not or not okay on your own.
> You’re assuming you’ll still have the employee if you refuse.
If the employee quits, you're in this situation once (and you'd be in it anyway). If you allow it and set a precedent, you might end up in this situation far more often and with worse consequences if you decide to change your mind.
> The point is that once you have no leverage over employees [...], you cannot establish what is not or not okay on your own.
Sure you can. You just need to find people that are okay with what you're okay with (and the same thing in reverse, of course).
I don't think leverage works in this case either way. If you have employees that are willing to let you stand in the rain and sabotage your business [0], you need to find new ones anyway. Leverage only let's you avoid the inevitable for a small bit in exchange for burning a bridge.
[0] I'm not saying that this is necessary the case in OPs scenario, but it plausibly might be.
The point is that once you have no leverage over employees (because their livelihood doesn’t depend on the job), you cannot establish what is not or not okay on your own.