When you put it that way, the answer is obvious:

Assume VCs are brainless profit maximizers who don't understand ethics. How do you get them to say "I'm gonna stop you right there"?

Answer: Make it unprofitable to collect this data. Change the incentives.

So really, the correct answer IS on the legal level. Make a set of laws which make it burdensome at best and completely unprofitable at worst, and then the incentives within the system aligns.

Agree with your point and the solution. Make it risky to operate - so that most VCs would wash their hands off due to legal risks. Kind of like what happened to the crypto space. But, it always gets worse before it gets better. Tons of rug pulls happened before SEC took action.