When a ship recieve a tractor beam, can we choose not to move the ship ? Or must we choose to barrel rool or move forward the ship ?

You can indeed choose not to move the ship. The reference card for the tractor beam tokens reads, "The first time a small ship receives a tractor beam token each round, the opposing player may choose one of the following effects:" Since it says may, the player can choose to not move the ship.

You can choose whether or not you wish to move the ship, but if you choose not to, you cannot then decide to move it if you apply a 2nd (Or third, fourth, fifth, etc) token in the same round.

21 minutes ago, joeshmoe554 said:

You can indeed choose not to move the ship. The reference card for the tractor beam tokens reads, "The first time a small ship receives a tractor beam token each round, the opposing player may choose one of the following effects:" Since it says may, the player can choose to not move the ship.

That's what I thought, but when I looked up the card it doesn't say "may". Did it get errata'd at some point?

http://vignette4.wikia.nocookie.net/xwing-miniatures/images/7/70/Swx41_tractorbeam-reference.png/revision/latest?cb=20160113000950

Yes, it was errata'd shortly before release in FAQ 4.1.1

4 hours ago, joeshmoe554 said:

Yes, it was errata'd shortly before release in FAQ 4.1.1

On page 2 of the FAQ.

1 hour ago, USCGrad90 said:

On page 2 of the FAQ.

Nice catch! I had to read it twice before I caught the change. When they do stuff like this I wish they would highlight the change.