When I get things off the feed, I always post a "like" symbol
I thought that
that is one of the things people use to determine that someone is using a grab bar, since some of the grab bars automatically "Like" rewards that they claim. See how quickly someone can be painted with the wrong brush due to assumptions made?
I drop anyone that I think is using a snagbar so that others can grab the rewards I post, not because they might get ahead of me.
I have a different approach. I have my neighbors in groups, and post each
limited bonus typically to just one of the groups. (Bonuses that are not limited, like crop mastery or ribbons, I post to all the groups.) Most limited bonuses I "spread around", posting one to one group, and then the next to another group. That way, if someone is running a grab bar 24x7, they're only grabbing a limited amount of what I'm posting, and only a small number of my neighbors are adversely affected.
The thing that I'm most concerned about is people using grab bars to grab bushels from the feed, bushels that they
don't need for crafting or for getting mastery bonus. The idea of that really steams me up - people grabbing bushels and then using them for pig slop, or just sharing them back to their feed where they go uncollected because the expire. I have a group for the people with the same kind of crafting cottage as I have, making the same recipe that I'm grabbing bushel's for, and I typically post those bushel bonuses just to
that group.
I don't get into the husbandry stuff (special types of horses or cows) but I suspect that an approach like that would work well for folks who are into that stuff: Sharing rare animals with other people who are breeders.
In the end, I really hate the whole "posting to the feed" approach. I'm playing FarmVille; I'm not playing Facebook!
I wish they'd get rid of all the posting to Facebook and just have something
inside the game where things get posted. That would get rid of all these issues.
By the same token, there is a big difference between dropping the balls in the pockets by hand and using a better cue stick, and I do see a lot of FarmVille players going way off the deep end with their suspicion of others "cheating". Often, that suspiciousness gets to be as silly as ordering the cards in the deck before a round of solitaire. 
