Well it looks like we got a big ol' coal stocking for christmas this year…

https://www.pixiv.net/info.php?id=10405

For now it seems easy to bypass by changing the location setting to Japan (no VPN needed yet). They do not seem to say anywhere what exactly is blocked. Realistically this can't be based on the presence of tags, so I think it's just all R18-G work that gets blocked if your location isn't set to Japan.
The works still show up as being blocked, which is better than a ghost ban imo since it lets people know if they're not able to see anything.