I'm not trying to start an argument or anything, but I'm a little worried.

Does anyone feel guilty about getting Fastpasses early in the morning and using them much later, well after the "window"?
I never felt at all bad about using Fastpasses the "traditional" way because I thought the park guides explained how they work very clearly. You get your Fastpass, you go enjoy something else for a while, and then you come back
within the window listed on the Fastpass. I figure that the average visitor can rightfully be expected to read that guide or ask a CM what Fastpass is about.
But the official guides don't say anything about the "come back anytime after the start" trick. In fact, I read a LOT about the Disney parks, especially before a vacation, but did not know anything about that trick in 2005, nor even in 2008 when I visited WDW. (I did read about WDW on the DIS boards and read an older version of the Unofficial Guide to WDW, and I don't think I read the trick at either one of them.)
I'm guessing that if
everyone utilized that trick, that Fastpass would not work nearly as well later in the day...you'd have several hours' worth of people or so all trying to ride Space Mountain at 7 PM, which would lengthen the Fastpass line.
I want to get the most of my limited time at
Disneyland (which will probably be a lot busier than WDW was, even though I'm going at about the same time). And obviously if someone happens to get a Fastpass and then is delayed in a way they couldn't predict, or if someone has a reservation during the return time, coming a bit late is OK--I believe that's why the CMs don't consider the ending time.
But I'm worried that I'd feel bad doing something that, if everyone did it, it would make the average person's experience worse.