ToXey: dumping is for items you no longer want. Using it to pile lots of items onto the same square is cheating, no ifs, ands, or buts about it. The fact that it's also one of the few ways to easily say "move these items over here" to your dwarves is a problem, but the answer is not simply to make the current cheat easier to use.
Technically it is bug exploitation, not cheating. Perhaps it is intended, perhaps not.. who knows.. Now what I do.... Using Dtil to change every vein of microline in my fort to adamantium IS cheating... But he is doing things within the framework of the game... and since this is a single player game... well I say go to it.
And until we get multi level stockpiles, and the ability to consolidate things better in a stockpile it seems a decent work around, certainly not grounds for calling him a cheater. (I mean honestly, why only 1 sock per square... how many pig tail socks can you reasonably fit in a single square? maybe a 1000 or so at least?)
On the subject of the anti stockpile.. this has come up in a few forms, and I have to think it might be usefull, but complicated... Like applying it to a massive area and have them haul away only the stones you want and the rest will get covered in magma when your done.