On the East and at the old US we have always had the most open time of any airline out there. Every airline has some amount of open time but we have the most.
BHs get what we call a "block" each month, or what others may call a "line", and a block is worth a certain amount of time. The blocks vary in time, lets say from 75 hours up to 85. This is "company time" and block holders here are responsible to fly it.
At most airlines, the block you get is the block you fly. Not here in US East. Here we have always made our company open time available first to BHs so they can "trip improve" if they don't like a trip in their block. This is a great benefit for BHSs (however, a lot of this open time could be used to add more blocks).
When a reserve says a trip is "stolen", what has really happened is a BH has taken a trip from open time and is flying on their days off, therefore overflying and, per our contract, not allowed.
Anyway, the open time for each base for the next day can be scene in our Catcrew system. When PHL has 3 1/2 pages of open time on a certain day, that's A LOT of trips. Open time is what is eventually covered for the next day by reserves at 3 p.m.
There are a few scenerios as to why open time disappears before a reserve gets it, but to put it in simple terms -- a BH takes it.
Now, there are many ways our contract allows BHs to pick up trips on their days off and it's legal. The ETB or trade board for instance. Or, if they have gone over their company time they must drop a trip in their block to bring it back down. Many don't do this for obvious financial reasons. They should be disciplined but often it is just overlooked by supervisors. Schedulers will award open time to a BH and not care that it puts a BH over. Their job, as they see it, is just to make sure it gets covered, and BHs get first choice.
Overflying happens throughout the year but seems to impact reserves more in the winter and especially in PHL because of seasonal flying. It may not be the same people overflying month after month but when done as a whole it has a cumulative affect on reserves.
This was my best and simplest take on the matter. It's actually a bit more complex. I'm sure I have overlooked some things either for simplicity sake or because I have never been a block holder so I'm not as familiar. I'm sure I will be corrected.
As far as the imbalance? Where do I start? It lies in the fact that reserves are written up for anything and everything. The imbalance lies in our earning potential taken away. The imbalance lies in the fact that 19 year flight attendants are on reserve. The imbalance lies in what other airlines and other AFA members have. The imbalance lies in rest requirements, 24/7 and being on call 24 hours a day for six days.
The fact is, something can be done about our reserve system. Just look at other airlines for God's sake. Look at other AFA backed reserve systems. Something can be done. Side letters, rotating reserve or like Delta, no reserves.