This came up at our regional this weekend. The situation is the use of Jyn's ability, "hair trigger" and the command card "Element of Surprise." Beginning of r2, Jyn activates from a spot where she has no LOS to any opposing character. She proceeds to double move to a point where she now has LOS of 3 of the opponent's characters. The opponent proceeds to activate their Han Solo, causing Jyn's Hair Trigger to activate. The Jyn player proceeds to play "element of surprise" for her attack. Element of Surprise reads:

Now, technically, the Han Solo did not have LOS to Jyn at the start of Jyns activation, allowing this card to be played. This is how it was ruled and we moved on. I guess the issue at hand is, how are we supposed to keep track of who had LOS at the start of an activation. What would've happened if the opponent didn't activate Han and Jyn didn't activate her Hair Trigger until 5 activation's later? Are we supposed to keep track of where she started?

There's an existing ruling. "start of your activation" should be interpreted as "start of the current activation".

(There could be further clarification in the next FAQ.)

(You can find other discussions about Element of Surprise in this forum.)

36 minutes ago, a1bert said:

There's an existing ruling. "start of your activation" should be interpreted as "start of the current activation".

(There could be further clarification in the next FAQ.)

(You can find other discussions about Element of Surprise in this forum.)

I think that makes sense. How can you definitely verify that Jyn had LOS if say her move happened way earlier in the game?

By the new FAQ ( https://images-cdn.fantasyflightgames.com/filer_public/80/b6/80b64200-dfe6-4963-8eea-51e806b31d8d/swi_faq_v30.pdf ), it looks to me like it does still work:

Quote

Q: If an elite Imperial Officer uses “Executive Order” to cause a Stormtrooper to attack, can I play “Element of Surprise?”
A: Yes. You can play “Element of Surprise” even if it is not the attacker’s activation. In this case, “Element of Surprise” checks if the target figure had line of sight to the attacker at the start of the current activation, not the attacker’s last activation.

Q: Can I play “Element of Surprise” during an attack during the end of a round?
A: No. “Element of Surprise” can only be played during an activation. It cannot be played during start or end of round e ects.

Q: If an attacker plays “Element of Surprise,” then the target is changed with “Bodyguard,” does the attacker still remove a defense die?
A: No. “Element of Surprise” removes the die from the original defender’s pool before the target is switched. e new target still has all of its defense dice in its pool.

Q: Can Darth Vader perform an additional action from “Lord of the Sith” if he defeats a gure a er playing the card?
A: Yes. “Lord of the Sith” provides a passive e ect for the duration of the activation.

So, by the second answer, Element of Surprise can only be played "during an activation," but it doesn't say "friendly figure/group's activation." Your opponent's activation still qualifies, and by the black text (from a previous FAQ), "Element of Surprise checks if the target figure had line of sight to the attacker at the start of the current activation, not the attacker's last activation."

It's a little hard to set up Jyn to have Line of Sight to a target that doesn't have LoS back to her, but wholly possible (peek-a-boo corners, meat-wall diagonals, etc).