It also violates the whole spirit of "don't ask people at work"
I have spelled this out to people who ask out my employees @ their place of work, something like this:
"look, if you as out/hit on Jane when she's out at a bar, she will say yes, say no, or possibly say 'go to hell, you're being creepy'.
Since this is Jane's workplace and she is in the job of dealing w/ the public, saying 'go to hell, you're being creepy' isn't really an option--she's under orders to be polite and professional and not swear at people.
If you wanted to see Jane outside of work, there are ways to do that that don't force her to try to find a polite way to say 'no' if she's not interested.
If you're in a situation where the person you're asking can't say 'go to hell' to you -for any reason-it's a situation where you shouldn't be asking her out"
None of them got it even after that.