I'm all about leaving no trace and being a respectful hiker, but I think that the right kind of Trail Magic is a great thing that happens on the trail! Seriously!
The idea is that long distance thru-hikers (and in some places, shorter distance ones, too) might appreciate getting some extra delicious supplies while out on their hike...and I can't agree more! I think that (of course) the things should not be put in bear territory and that appropriate clean up should always be done, but other than that, this is a great way to do something nice for those out there enjoying nature!! Keep it going!!!
For those that don't like the traditional "food drops" like the coolers above, though, what about this? A table set up. People can stop and enjoy, grabbing what they can carry, and the clean up is done by the people doing the tables. What could be wrong with this?
Also, Water Cashes are always great, because water cashes save lives. REMEMBER to NEVER rely on water cashes if you're going hiking, they might be out!!!