(CS83)
During the encounter phase, players cannot optionally engage Goblin Sniper if there are other enemies in the staging area.
Forced:
If Goblin Sniper is in the staging area at the end of the combat phase, each player deals 1 point of damage to 1 character he controls.
"other enemies" mean other than this one card or other than each card named Goblin Sniper.
If there are 2 Goblin Snipers and first option is true than it won't be possible to engage any of them untill end of game.