Further to my post above form June 11...
I noticed the updated rules on AC's page and added them to the wiki. In case no one looks there 
https://www.aircanada.com/ca/en/aco/...ure-suite.html
* Air Canada Signature Class customers travelling on an Air Canada-operated flight (to Europe, Asia and South America) originally booked and ticketed in the following booking classes will be eligible for access to the Air Canada Signature Suite: J, C, D, Z, P. Only Aeroplan flight rewards booked as a Business Class Flexible Reward or a First Class Flexible Reward in J, C, D, Z, P, I booking classes are eligible for access. All bookings in R class (including, but not limited to, eUpgrades, Last-Minute Upgrades, and AC Bid Upgrades), Aeroplan flight rewards booked as a Business Class Lowest Reward or a First Class Lowest Reward, Star Alliance Upgrade Awards, Business Class flight rewards booked and ticketed by partner airlines, and I (including Star Alliance Upgrade Awards), as well as bookings made during irregular operations where the customer was not originally booked and confirmed in one of the eligible booking classes, will be excluded. Eligible customers may not invite guests. Access to the Air Canada Signature Suite is not available to customers travelling on promotional tickets or employees.
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