Interesting.
The documentation says that when an object is requested from the cache, if it exists in the local cache then
the reference to the object is returned immediately without contacting the server
(MSDN)
in which case, the remote cache cannot possibly be notified that the object is being used, and this would seem to support your thought that the object could become a candidate for eviction.
There's some discussion here that suggests the local cache also uses an LRU algorithm, and I'd be interested to know whether the two caches do any communication/synchronisation of their LRU timings.