TLDR
Sthephen is right.
Snipes are good.
Arcs level 80 are bad.
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Snipes by themselves are fine. If the guild allows it, and most guilds do, then its just part of the everyday etiquette of the guild, and after a short time, the guild mates will learn and manage it.
The problem is the Arc. Most of the player have Arc up to level 10. This is just not enough to compete against the players with Arc level 80. In a lot of guild swaps, there come a situation where you can snipe the 1st/2nd places. This option is possible at first only to the high Arc players, and no other. So the 1st/2nd places are assured for those rewards, while the low level Arc players (or no Arc players) cant even enter the competition for the 1st/2nd place or they will lose 10's-100's of FP's. So even if the player is ready to snipe, and is 24/7 on the computer and on all the swaps, he still cant compete for the 1st/2nd place.
This inability to compete is the problem here. Not the snipe by itself. The Arc allows very few players to get the best rewards with minimal competition. It is maddening to be sniped a few times by high Arc players on a reward that I identified as good, swapped for, and wanted, but couldn't fight over it at the end as I didn't have the tools (Arc level 80). I love snipes and the contention over the rewards, but I couldn't fight over it!
At the end I joined the winning side, and leveled my Arc to 80 so I could fight over those rewards.