I have no idea if the agents can see the blocked seats.

Yes the system does free up seats as they are required (note this is not gold blocking, it blocks seats beside you pretty much whatever your status), but if you are gold then the seat beside you becomes a candidate to get released much later than for other status levels. lots of discussion on that in the very lengthy thread already referred to in this thread. More than happy to follow up further on that thread if you have questions, as now doubt would cws, but i would prefer not to create a 2nd length thread on the topic here.