This may seem picky, but I find it irritating (when trying to sift through hundreds of Smart Matches with 2 or less matches) and I have to hit "reject", "ignore tree" and "confirm ignoring tree" before I can move on to searching for the next needle in the haystack. I'm already limiting my review of Smart Matches to crown icons (indicator of more current trees and more serious researchers), but my clicking finger is pooped!
Technically you don't have to officially reject the actual match. Likely you will get other matches for more recent trees which you can confirm to give the system more info. I do admit that I sometimes have rejected or even confirmed a match on a tree I was about to ignore, but that's generally been a mistake and an exception. Sometimes if a tree has several matches, only one of which is actually wrong, I will reject that particular one before I ignore the tree.