I mostly agree (although sometimes it is necessary to talk to someone about it); it would be better to actually have good documentation (so that you do not need to talk to someone about it).

A warning label like you mention is a possibility if that is considered to be necessary, although I think it might be better to have a file that you can download and read (or request by mail or telephone or fax, if this becomes necessary in some circumstances; do not assume the computer always works and is compatible with your file), instead of a searchable wiki.