Do some persons send merits in advance before reading a post? If yes, it's not a good habit. Unless it's someone I know that has been producing quality topics, even at that, I'll still be able to read through to determine the amount of merits to hand out.
As a Merit source,...
Some of the good posts are very long and when my time is running out, I'm sometimes leaving a tab open to read the rest later, while already distributing some Merit after reading like 50% of it. Sometimes I'm also forgetting that I've left a tab open and therefore the rest goes unread sometimes...

Very understandable as a merit source who is determined to spread his merits across quality posts. Some of the posts are quality and also lengthy. The irony of it, is that you can meet such a post when your are not in the mood to spend enough time in the forum, maybe just to have a glance.
No doubt sir. The content will remain unique and as well stand the test of time. But the reality is, only a few will be willing to invest the type of effort that brings uniqueness when there are simpler ways to produce a look-alike.
Most often, this comes from the fact that the one who uses the look-alike does not have a complete understanding of the topic that he would like to highlight and explain. I'm always surprised that duplicated or paraphrased topics and guides get merits, as it's clear at first glance that the information isn't new.
It could be that you are able to spot an idea that is not new at glance because you definitely have an idea of the topic or the ability of the topic creator. You are just too good at rating people's intelligence and ability based on the kind of posts they made previously.
This is your greatest tool of catching plagerists

Once you see that a post is somewhat lengthy, grammatically organised, cool worded and formatted, you will assume they copied from internet. Funny enough you are always correct.
In your words you will say the person is trying to portray his/her to be more intelligent than they actually are
