Is punning with homophonic kanji common? I recently discovered that the mascot for []{} is []{}. Answering whether this was a deliberate pun is probably impossible, but I'd like to know, in general, is it common to replace one kanji with a homophonic kanji for the purposes of punning?

I think it's pretty common, although not necessarily punning so much as just a play-on-words. I can't remember but a couple right now. I'll edit in more later if I remember them.

> * → I got the committee's permission. Surprised, I responded "(Is it) Really (OK)?".
> * A major station I used to frequent had a nearby building called "Sun Plaza" written as , as seen here on Google street view:
>