First let me say: I know there are no-lifers out there like me who legitimately are at every node or crafting for 4+ hours per day. However, there are a huge amount of bots who gather from nodes.
There are a few ways you can easily spot a gathering bot:
1. They are not in an FC, and if they are in an FC, all their members are below level 30. (You can check this via the lodestone.)
2. They have one combat class leveled and all gathering classes to 90.
3. When they are gathering, they follow the exact same path from node to node. A good example of this is at the ephemeral nodes to get aethersand at level 90 in Labyrinthos, Thavnair, or Mare Lamentorum.
4. Not only do they follow the exact same paths, their characters will also target the node before they land on the ground.
5. These bots will also often dismount/mount in a strange manner, much more fluidly than a human player.
6. If you attempt to trade block them while teleporting- which is against ToS so don't do it!- they won't move an inch. They will just try to teleport again. A typical player would run away and teleport or put /busy on and teleport.
7. Will not respond to emotes or tells, will not target you, will not move in any different way at all.
Crafting bots are harder to spot, but an easy way of spotting these bots is by checking popular items on the MB. Look at the signatures and use the player search function to find the crafter on your server. A crafter bot will:
1. Almost always be crafting in an inn room due to not having an FC, and requiring a place they will be unseen for hours on end.
2. Have only one combat job leveled, but all crafters leveled.
3. Will be able to adjust MB prices every 5 minutes or so, for hours on end.
4. Will not respond to emotes or tells.
There are some assumptions that must be made in order to pin-point a crafter bot, but there are far fewer assumptions with a gathering bot.
Please, if you notice a gathering bot, report them to SE. By not properly addressing these bots, MB prices are ridiculously low, disincentivizing actual players from gathering and crafting for gil. It's also completely unfair to actual players who follow the ToS.