Heck, you don't even need to mix up a personal and business AI subscription. For the vast majority of folks one day their IDE "updated" and a bunch of AI features suddenly became available. Free, no sub needed. A dev starts using them (because, why not?) and lo and behold the company's code got shipped out in an inference call and is now scheduled to be in the next training run. Oops.
IDE updated? It’s the company IT’s job to perform testing before distributing those updates. And also their job to use whatever managed settings to disable those unmanaged AI features.
Actions speak louder than words. If the company doesn't even supply and require work devices, they don't effectively consider their code to be valuable IP.
Of course the company can still consider their code to be valuable IP.