Is it a local match? If yes, does it specifically say in the WSB that swingers must be activated prior to engaging?
If the answer to both questions above is yes, then you may not shoot them while they are just sitting there. Otherwise, go nuts. It is rare to be able to engage moving targets before they are moving at a major match however, so if you would like to get the best training possible out of the local match scenario then activate first. Might as well utilize the training opportunity you have.
Gooldy takes win with the serious answer.
At level 1s/local matches often they don't put enough vision barriers in place. So they just stipulate that the swinger must be 'activated' before 'engaged'.
I once thought I was a clever fuck when a local match had triple swingers and I realised I could see a small strip of about 3inches of each target. They were tough shots but perhaps I though easier than activating. Yep 6 procedural. D'oh. I argued my little heart out and got nowhere.
If you plan to engage it before activation listen carefully to the verbal briefing AND read the written briefing which should be posted up somewhere on the stage.