What smell test? I very much remember cookie banners being a problem way before the GDPR and so does the rest of the web:
(2012) https://www.bbc.co.uk/news/technology-19505835
(2013) https://econsultancy.com/17-useful-examples-of-eu-cookie-law...
(2015) https://superuser.com/questions/725312/disable-all-cookie-wa...
(2013) https://ux.stackexchange.com/questions/40687/we-use-cookies-...