It's, uh... interesting to see that the bikini crowd has made their way down here. I hope you intend on behaving better than those you associate with.
As for your question: 99% of the time it's extremely obvious. The other day I saw a bunch of RE'ers on Twitter argue with some guy who claimed to be a Flat Earther and a nationalist. The very first thing you'd see if you visited his profile was a pinned tweet reading "geraffs aren't real".
My best advice, therefore, is to think before you write. There's no panacea, there are trolls in every discussion, and unless you exercise the bare minimum of critical thinking, you're gonna get caught up in the crossfire.
As for the monetisation aspect - while I personally think trying to make money off FE is a big no-no, it does nothing to prove of disprove someone's intentions. There are honest FE'ers who make money through merch, and trolls who don't make any money.
Pete-
I recently came to this forum and had never known of the FE movement or belief until about 3 days before that.
Personally it doesn't do much to/for me whether the Earth is flat, round, or rectangular - so initially my interest was peaked because I was curious to learn what people who held this view had read/seen/experienced, etc so that my eyes could be opened to new information and a different way of thinking/seeing.
Then, based on what someone claiming to be an FE'er wrote on another, unrelated site, I had thought maybe this wasn't so much about the earth being flat as it was that a group of people had taken that position as a way to try and get others to question what they thought they "knew" - to help wake them up and open their eyes so to speak. That was further reinforced by some of the things I read at this site, for example Zeteticism, and the welcoming of other, non FE ideas/theories that challenged unrelated sacred cows.
But that's based on my often faulty interpretation and intuition, and since coming to these forums it's been hard for me to tell someone's alt from a troll that's just trying to be disruptive for no reason. For example when a response seems to have missed the point of the post completely, is it a troll being disruptive or is it an alt seeing if someone is going to get pulled down a rabbit hole? Or if a response is almost exaggerated in how one-sided it is, is it a person who doesn't allow for any view but their own or is it an alt holding up a mirror for the original poster so they might see their own close-mindedness?
I'm asking all this because debating or discussing the shape of the Earth, with no other goal beyond that, is very low on my list of priorities. So if that's the sum of this whole thing then I can move on, though I'll be sad and disappointed it wasn't what I had thought since I had been excited and relieved(?) that after many years I'd found some like-minded people (like minded at a macro, how we see things sense, not like minded in that we all hold the same opinions/beliefs) who were on a similar quest as me.
So if you could let me know I'd appreciate it, because the flipside to me being able to and okay with seeing through the veil, is that sometimes I see things that aren't there, and I have to check in and make sure I'm not "Beautiful Minding" it.
Thanks.