It's their free time, they can do whatever they want with it. If there is something unlawful or disloyal well then you deal with that situation, but you can't tell someone "I will tell you what you can do in your free time just in case you may do something I don't like".
Also, let's be honest, how much harm can a 1 person project do to a multi billion corp? It's a fallacy.
Also, let's be honest, how much harm can a 1 person project do to a multi billion corp? It's a fallacy.