That just creates another problem: if you're taking any measures to reduce tracking (ie. clearing cookies on shutdown or using temporary containers), this won't work. If anubis was being deployed on a site that a user visits often (eg. HN), the user might be convinced to whitelist it, but most anubis deployments are on random blogs or fediverse instances that I might not visit again in months. I'm certainly am not going to whitelist those sites, nor am I going to enable cookies wholesale just to avoid solving challenges.