As a >2k user on SO, I often review suggested edits. 

- If an edit *formats* code, I will **accept**.
- If an edit *changes* code, I (along with everyone else) **reject** it.

In fact, I've yet to see an edit that changes anything in a code block other than white space that isn't invalid.

So, my feature-request is to **forbid <2k users to suggest edits that change code blocks** (*except whitespace*).

Note that code formatting includes both addition *and subtraction* of whitespace.

At the very least, put a big banner in the review queue that says 
> WARNING: This edit changes code. There is a high probability it should be rejected as invalid.

I believe this minor change to the system would lessen the number of rejected edits - every rejected edit is an edit that wasted at *least* three users' time.

I would think it's obvious, but those users should be able to change code in their own posts.