I mean: one should not simply copy an opentype font into (context) system and expected things to work. Checksum should be check at every runs, which is useless most of the time: in a production env. I don't change fonts for long time , and every change is tested. Maybe a lua script to install fonts is better -- we can eventually think to a wxLua gui interface .
I'm not sure. In a desktop environment the user will just update the OpenType font via the OS (e.g. replace a file in the usual OS font directory). From that moment on the font will work in almost any application... don't you think it's reasonable to just have the updated font work in ConTeXt, too?
Addendum: should an updated font not work out of the box (i.e. change the looks of an existing document) then I think the usual DTP suspects issue a warning. Oliver