I wonder if someone ever attempted something like that?
I've never come across such a case, but it seems like it will be too much work for too little a reward and would expose the user's alt potentially.
Firstly, merit sources are selected from the dedicated users to the forum, meaning a user would need to have risen to a certain rank and built some reputation, risking that for a couple of merits around alts doesn't seem worth it, and if a newbie in need of merits applies as a source, it would likely not get much attention.
Also, as I said earlier the reward is relatively small, checking through the suggested posts in this thread only a few received a few merits after the application was made, so there are no guarantees.