I agree that the Reserve Call Out Procedure is a crock and that is exactly what Future Reserves 2020 paper spelled out and wants fixing ASAP.
On the subject of not answering a mobilisation/call-out letter; if you don't have a good reason for replying then you can be sent down for 3 months and a hefty fine (it's in RFA96). I don't believe "I haven't opened it" would quite cut it! Also, RFA96 spells out the offence for inciting AWOL or failure to report - some of the words on this thread could be construed as such...
Finally, Reserve Liability is set out very succinctly in the Service Leavers' Pack. Here's a link to the 8mb document (beware lots of big pictures!)
http://www.mod.uk/NR/rdonlyres/68DEE...UIDE_P4562.pdf
LJ