Absolutely, and not even assault. If an employee of mine was making people feel uncomfortable and potentially damaging my organisation's brand with their behaviour, I'd want to know immediately. And at the very least have a strongly-worded conversation about it. If they then showed no signs of adjusting their behaviour, I'd remove them from a position where they can damage the brand any more.

Letting it get to the point that police are involved is waaay too late.

Tbh if I heard that an employee of mine had a fully-consensual sexual encounter with a client, I'd be asking pointy questions. This is a business not a dating service or a swinger's club. Keep it professional, people.