I wasn't 100% sure on the details with that
but the timeline article someone posted lays it out.
Tuesday, March 30
News begins to surface that Vancouver center Adam Gaudette left practice halfway through the session. During his post-practice availability, head coach Travis Green reveals Gaudette "had a positive test come in this morning and we're following NHL protocol and he left the ice."
The positive test was from the March 29 batch. Gaudette is added to the NHL's COVID protocol list later in the day.
Wednesday, March 31
The Canucks and the visiting Flames hold morning skates in preparation for their tilt that night at Rogers Arena. The Canucks skate at approximately 10:30 a.m. PT and the Flames an hour later.
While the hope was that Gaudette's test result was a false positive, Green confirms Gaudette is in COVID protocols but that it appeared just one player was affected and the game that night was going to happen.
"Last night we had a pretty good idea we were good to go this morning," Green said, adding later: "We're preparing to play. We haven't been told otherwise."
So while what you say is true about the practice they
still held the gameday morning skate the day after with a positive Gaudette test
hoping it was a false positive. As far as Covid is concerned is a gameday skate isn't much different than a practice, and there's a reason why like 3/4's of the team has been infected.