I've already demonstrated to you how there is no rock/hard place for you to get stuck in. You can avoid the problem - however big or small that problem really is - simply by rephrasing.
If it's no big deal to anyone then why is it a big deal for you? How do you handle the grafitti issue? By referring to it for its condition exclusive of how you believe it may have occurred.
"Damage to paint on the south side of the garage, estimated cost to cure is less than $500."
You don't need to use the word that some wound collector might want to latch onto in forming the complaint about you being biased.
Don't feed the trolls. How hard can it be for appraisers to understand that the most expedient way to resolve the problem is to avoid it in the first place? To crush the hopes and dreams of the professional litigants before they can even get going. To deny them the opportunity to grasp for the free go-away payment. To act aggressively and proactively on the issue rather than passively sit back and play the odds that they won't have to react to the complaint after the fact.
The game is chess, not checkers. And appraisers are better served by at least trying to stay one step ahead of their critics. I'm not being pro-bleeder here. I'm being pro-appraiser.