If true this is really disappointing news. It looks like another Canadian airport is following the nonsense of YYZ and segregating terminals by what flight you actually have. Meanwhile in the states i can access whatever terminal I damn well please so long as I have a same day boarding pass departing from the airport. You may think I'm splitting hairs here but there are tons of legitimate uses for accessing terminals you technically shouldn't be in.

In particular, as OP noted there are often better lounges in the other terminals. In the case of YUL it's the difference between a MLL with a shower and one without. And AC would point out that as a domestic pax you can access that Intl MLL in certain circumstances. At other airports I've been to this month different terminals means the difference between the *A lounge at LAX with it's shower suites, outdoor terrace with tarmac view and good food at TBIT versus no lounge since I was travelling DOM as UA Gold. In IAD it meant the difference between the TK lounge with it's shower or no lounge since I was travelling DOM as UA Gold. Just yesterday when I was at Newark it was the difference between accessing the wonderful LH lounge in Terminal B and SK lounge there as well with great menus and facilities versus sticking to the United Club at Terminal C with it's cash bar and cookies!

This is also going to be a double whammy for Westjetter Elites mark my words on that count. Why? Because many of the airline lounges have backed away from the contract model. Most recently AC pulled out of priority pass. As the lounge options become more limited and access to other terminals is denied you'll struggle to find any terminal to use. Which is fine if you're a fat cat like me who flies * exclusively and has status but for everyone else... I'm not so sure!

Safe Travels,

James