Bad ethics?? This is fantasy baseball here, not Enron or MCI/Worldcom.
I do that sort of thing all the time. E.g. : If the pitching categories are close heading into Sunday, I will check to see if my opponents pitchers are playing in the morning and then pick up a pitcher off the waiver who is playing later in the day and then decide whether to start him or not based on how my opponents pitcher did earlier.
It's not like I'm wrecking someone's retirement fund.