I am not saying me, but there are people who got many merits when they are using signature, so it is kinda different from rivange's hypothesis.
The current top 3 most merited user (LoyceV) is on ChipMixer's campaign.
The top 6, hilariousetc is also in the same campaign.
The top 8, Lutpin is using a paid signature.
The top 12, The Pharmacist is also with ChipMixer.
and the list goes on... actually, a big part of the top 100 most merited users are in a signature campaign. So, I think it's safe to assume that this doesn't mean a lot.