Disable signatures after inactivity for x days

I have been thinking about this for a bit as I run a forum in a niche where people put images, tickers etc in their sigs which often expire and leave broken images and links over the years.

Is it possible to have it so a persons signature will automatically disable after say they have been inactive for say 30 days and re-enable once they start posting again or leave a message for them to contact me to re enable it, I don't want their signature to be deleted, just disabled from showing. Is that resource heavy?

Another advantage is it helps to deter spam. Recently I came across another signature for a very old user where someone at some point had guessed their password and snuck in a link in their signature. Plus it also deters old members from coming back years later and adding links in their signature for their own gain without posting to the forum again, which can go on unnoticed as it's displayed in previously buried posts.

Atleast, if they have to post again for their signature to display, someone will more likely notice if there is an inappropriate link and report it.

[fyi safari did freeze towards the end of this post but autosave kept everything so no biggie]