Robert’); DROP TABLE Students;–

https://xkcd.com/327/

At least you’re not rewarded with more ads.

There are still many other instances that accept signups, so I don’t think temporally disabling lemmy.world signup will hurt lemmy.

However, having a popular client incompatible with a popular instance will annoy existing and new users.

One way to check is to do a search. e.g. for lemmy.world, google site:https://lemmy.world/