I often see, what I refer to as, implied erhua written in shop names, advertisements, on menus, etc. Take the following for instance:
You'd rarely ever hear
gé pì read without erhuaization. So the idea is that, although 儿 is not written, it is certainly implied.
Technically it would be considered to be written incorrectly, as the example above should be written 嗝儿屁. But is this some kind of phenomenon that I'm half aware of?