Now, we all know you can't attack a base until it's owner goes offline. CoC matchmaking system prioritizes such active players.
So, if you raid when these players are online your chances of bumping into an abandoned base are increased. I am not saying you'll run into abandoned bases all the time; but the probability of running into such a base will increase. I have tested this in trophy range of 1680-1720.
1685-1699 trophy range has been the best for me. 1 out of 7 opponents turned out to be an abandoned base with loot in the range 150k to 400k.
I have already posted the tested time intervals in my previous comment, you can experiment. :cool:

