I hate the discourse (not you, but in general, especially tweets like these) about scouts being at games.
15-20 scouts are at every single NHL game. Scouting is not something that starts a few weeks before the deadline and then trades are made. A scout doesn't watch a player 3 times and then a trade is made. Its constant. They are constantly updating files on every player in the league.
There are also reasons to scout that don't involve trades. There is scouting the opponents system, pp, pk, etc... to attack it when you play against them.
On top of that its the same names cause a guy like Andre Savard (And many on that list) doesn't live in New Jersey even though he works for the Devils. He lives in Montreal and goes to virtually every game. He's constantly scouting both the Habs and the opponents. Same in every NHL city. A bunch of pro scouts live in those cities.