@kiwidude - That would be a possibility, though if the shortcuts were assigned by line they could have different effects. For example I usually copy from "Main" to "Network", but if I switch libraries that same first menu line could be from "Amazon freebies" to "Main" and the second line could be "Amazon freebies" to "Network", similarly with "Epub freebies". Still I suppose it would be fairly easy to figure out Ctrl-1, Ctrl-2 etc. by context, and at least it would ensure that it wasn't performing any kind of deletion.
@kovid - I recognize that it's difficult to change an existing menu structure. I just think it's unfortunate that the current layout could make deletion errors more likely, particularly when doing some high volume/frequency copying.