Slightly different: legitimately earning AMs and PC points for the same stay
What I have started doing recently is booking my ICH stays through the Canadian AIR MILES Shops portal. This takes you right to the ICH booking site and brings up one's default account. This way I can double dip, since I get 1 AM for every C$20 spent for the room, in addition to my normal PC points and bonuses. (Actually, I triple dip by charging the stay to one of my affinity credit cards!)
AMs post quite quickly after the stay as I had two bookings for last week in Singapore and Malaysia and both have now appeared in my AM account, within days of the PC points posting to my PC account.
So this may be the best way of earning AMs for stays at ICH properties.
(Note that this also works with the Aeroplan shopping portal which also accesses the ICH booking site. Both AM and AE portals can be used to access SPG properties too. However, AE takes forever to post miles earned.)