In fact, things are worst than I said : for the Memcached ticket registry, the ```getTickets()``` will throw an Exception : https://github.com/Jasig/cas/blob/master/cas-server-integration-memcached/src/main/java/org/jasig/cas/ticket/registry/MemCacheTicketRegistry.java

We could have a separate token store but I'm not sure that it would be so easy : we would still need to remove expired tokens, and so on...
At that time,I don't know what is the right solution. I tend to search a solution in an another war : isn't it possible to have an improved ```OAuth2Authentication``` with the TGT id ?