The Reseed Request sent by the "Request Re-Seed" button goes to the up-to 120 last known members having completed the download.
However it does not go to the original uploader (unless his torrent client has sent a completed information and he's still within the 120. Normally the uploader isn't starting download and therefore doesn't complete it).
A comment made to a torrent generates a PM "New comment on …."style to the original uploader (if known) and other members who have commented. The "Please reseed this torrent." comments when we test a torrent for being dead is to get the original uploader's attention and usually combined with a reseed button click.