I've always seen this simply handled by disclosure: * At hire time provide a list of "my ip" and "ip from previous employer that may be controversial here" *

I've always seen this simply handled by disclosure: * At hire time provide a list of "my ip" and "ip from previous employer that may be controversial here" * At personal project start time, get a document signed from management saying "this is not related to $employer, and does not count as related work" * At exit time (particularly when there is post employment IP or non-compete) get a document agreeing that "this IP was from the employee to the company, this was not. It sounds like a bureaucratic mess, but it's like 10 minutes of hassle here and there, and saves a bunch of issue, even in the future if say, the company gets bought out and the new owner has different views.