Do you really think it's stupid to consider asking a client whether they're okay with you sending their personal data to another company? Just assuming that only a tiny minority of them actually care seems a bit careless.

I don't like the EU cookie law either, but that's a completely different thing. The only thing they do have in common is that they make UX designer's lives a bit harder, but that's really no excuse.

Considering "their personal data" in this case consists of "what you clicked on my website", no, I don't think that should require any special permission.

I think you and I have different definitions of personal data. When I hear that phrase, I think things like addresses, income, contacts, and so forth, but not email or phone numbers (both of which are basically public info), and certainly not what you clicked on my site.

What someone clicks on websites is extremely sensitive private information. Extremely private sensitive matters of peoples' lives is directly observable in the things they click on websites.