Spoke with GM,YSB today.He learned of new security measures by a phonecall.Their group, GX, is to meet in YYZ on 23rd and 24th of this month.
His view is that GX passengers are/will not be able to use the MLL.("a slap in the face" were his words)
Seems the feeders are not even up to speed with the rapid fire changes at AC.
Another well used perk as an Elite member that is lost in YYZ.
Perhaps I will check-in at T2 and use the MLL,then the airside bus to T1.