From what I've heard people say (and what I've seen), the most common way to handle it is to simply write another character that sounds the same. In other words, the characters can be used as phonetic elements when it's needed. It looks weird (in the same way that spelling words phonetically in English can look word), but it's doable.

That's for situations where they had to write something by hand but didn't have their phone with them to check (otherwise they can just spend a second to look at the character), which isn't a common occurrence.