Just my opinion....hopefully at UPS we can accomondate as many off-line jumpseaters as possible. Personally, many offline crews have extended me the courtesy of their jumpseats.
As a business practice to save money, UPS uses the jumpseat as a mode to position crews versus paying for commercial tickets. These crews are listed using a higher priority than space available riders (both internal and external ones).
In my travels from Florida to ANC it is very common to have higher priority jumpseaters on flights between SDF and ANC thus limiting the number of space-avail opportunities. As more crew members get assigned ANC (as opposed to bidding by choice), the number of commuters will increase and the opportunity to find a jumpseat (SDF-ANC-SDF) will become more difficult.
Just my two pesos worth,
FF