And are warning shots ever a good idea?
From a practical standpoint, they're a waste of ammo. From a liability standpoint, they're a risk of collateral damage.
Would it come back to bite me in court? Probably not where I live. Your mileage may vary according to where you
live. Most states with castle doctrines generally require some articulated threat of harm. Running into a burglar while walking into one's house...well, most juries would say that was a situation in which a homeowner could get hurt.
It could be a really gray area, and every situation is unique. Generally, I'm not a fan of violence over property, but I could definitely see a threat of harm here.