I do not think that we should instantly tag people who fall under the category 'b' (which is not the case with OP). However, if the user displays a pattern of asking several members for this, we should tag them IMO. What do you think?
- People who find 'ways' to distribute merit either by opening new threads or offering services should also be prohibited as they inspire other shady activities to harness the merits.- For instance,threads like this : https://bitcointalk.org/index.php?topic=2819141.0 should also be discouraged.I see no point in doing it openly when you can just browse the forum and give merits if you come across a great post.
Dude I am jealous that morons are PMing you for merits. I wish they would PM me. I would gladly give them something they "deserve" 
The difference is, yours wouldn't matter.