from the CBA:
24.6
For the IIHF World Championships, the Clubs shall permit a Player to play for his National team provided:
(a) The Player's Club either did not qualify for the NHL Playoffs or was eliminated in
an early round of the Playoffs.
(b) No agent or representative of the Player's National team inquired as to whether
the Player would be willing to play for his National team until after his Club was eliminated
from the NHL Playoffs and any such inquiry was only made with simultaneous notice being
given to the General Manager of the Player's Club and the Player.
(c) The IIHF or the Player's National team agree to provide such insurance to cover
the remaining value of the Player's SPC.
(d) The IIHF or the Player's National team agree to provide such additional insurance
to cover the Player's loss of earning capacity as the Player may require
i'm no lawyer, but it looks like the owners can't actually stop a player from going. and if that's the case i'm glad it is. the owners own the teams, not the players. I say if they fulfill all of their obligations to their NHL team they should be able to play in the WHC if they want.