I would presume that it's fairly obvious that I've looked up quotes in the past to use on my blog--like this and this and this, to name just a few. It's the easy introduction to a topic that we all learned in high school: use a quote from someone (semi-)famous to open a subject, then either agree or disagree and you're off!
I've never felt that there was a particular ethical quandary in resorting to Bartlett's Familiar Quotations. To see the former Governor of Alaska (who is also known as Caribou Barbie) quoting Plato, however, makes me begin to question the ethics (or at least the wisdom) of quoting someone of whom you've never heard, or at the very least never read. Nothing on God's great Earth will be able to convince me that Mrs. Palin has actually read The Republic, The Last Days of Socrates, or anything else attributed to Plato. In addition, it seems that the "hour of play" quotation may be apocryphal--try to find out which book of dialogues the quotation came from. Let me know if you find anything, because I've been thus far quite unsuccessful.
(As one commenter on a blog I stumbled across asserted, "You learn more from reading Plato's dialogues than from reading Plato's quotations." Oh, snap!)