You are correct, the "tags" are just entries into the metadata, which is not size restricted. The Steemit platform restricts entry, not the BC.

I have begun sending out semi-automatic notices to users who are re-introducing themselves.

See example:

https://steemit.com/introduceyourself/@zuljalalil/latest-news-sphere-to-share-5o-token-only-for-registrants-9aacc3b8c57d5#@bycoleman/latest-news-sphere-to-share-5o-token-only-for-registrants-9aacc3b8c57d5zuljalalilbcintro1