That is obviously the greatest fear.
The question is, will they find a shooter not just capable of an 1800+ yard shot, but also fanatic enough to not care if the round hits an innocent target after a mile plus down range.
As you know, even with environmental factors correctly adjusted the chances of missing due to variables are greater than the chances of a hit, especially in a dense urban setting with tall buildings.
I'm certain an individual with the ability will not take the shot, due directly to the common sense required to be able to make it.
Not saying there aren't fanatic monsters happy to try, rather, I believe those folks no longer have the sanity for success.
Then again, I also would not disregard the earnest prayers of 74 million conservatives prayers either.