It very well could be the case, but what about the teams as well?
I don't believe there is collusion on either the players' part or the GMs' as it would be a bad move on either side to potentially face legal troubles during contract negotiations, and to a skillful lawyer a charge of tampering or collusion can be used in many ways to keep involved parties in line or penalize them if found guilty. More than that, I believe players and GMs have reasons besides the fear of being charged to avoid collusion altogether in this particular case.
On the NHLers' part, the contracts being negotiated here are individual ones, and it is true that these contracts will indeed set the market for RFAs now and for those who will look to sign contracts in the next year or two, so the NHLPA will also show its face potentially, but there is a whole slew of personal variables in play for the contracts themselves for each player (and their respective teams as well) in addition to their comparables, stats and everything else that justifies the pricetag of a particular player's contract. That fact probably means that even though the marquee RFA players probably do keep in touch with each others' situation and are aware of the market value they will set if they sign their deal, the very individualistic nature of these contracts and the way they're negotiated probably renders any collusion amongst the players inefficient and thus ''not worth it'' when put in relation with the risk of getting found out and facing legal action. Ultimately, the players will get paid and their agents will try to maximize that pay check in the few ways they can and that is either through indirect PR, hoping their teammates put additional pressure on the team, or holding out and not appearing in training camp/preseason/regular season games while hoping their GM finally caves in before they do, and that is quite the individual behavior, not something that you coordinate with everyone else.
On the GMs' part, artifically keeping RFA prices down might be a good thing as a whole, but they're also in direct competition against one another trying to establish and build the best team possible and their owners expect certain results out of them, so I believe that in this case the GMs' natural rivalry alongside the inherent difficulties that the tampering charges would bring is enough of a deterrent for them to avoid colluding altogether. They will however try to get their own players signed to the least amount of money possible in order to save their cap space and will be willing to use PR (basically making the player out to be a bad person through different ways in the hopes he receives enough backlash to force a signing) and start the training camp/preseason/regular season without the player to show him that they don't need him that much, hoping he gives in before their season gets under too much.
In the end, even though I don't think there is outright collusion in this case I believe there is at least a certain ''collegiality'' between the different parties involved, with players rooting for bigger salaries and shorter deals while GMs and their owners want to spend less money on bigger terms.
