Then they should be very open, up front, and explicit about asking for your consent, including describing what they will be collecting, and also making it very clear you can decline without negative consequences.

I'm fairly comfortable with data collection if the user opts in, but the current trend--dark patterns where you put out a blanket "we will collect stuff" disclaimer that lacks any specifics, while not making it clear what the consequences are of declining--is deeply troubling and, I hope, becomes illegal thanks to things like GDPR and CCPA.