I was at ASSp last month. Having seen thos topic before my trip I was more noticable on what the guests were using to fill their drinks. The curredt mugs has "100 years of mgic' theme on them. So the current mugs were noticeable. The sign say free refills for you entire stay. No mention of 'current' just stay. I did not see any mugs from other resorts but I did see some older All Star mugsand also super glulps from 7-11. The CM seem to keep a blind eye.
If one was to stay at more than one resort during a 'curent' stay I think they should be allowed to use them for their whole stay. Why should a gueest have to fork out $11 every time you change resorts. If you stayed at one resort you could use it for your entire stay.