[tex-live] Not so good experience with TL net install on windows.

[Karl Berry]

    I know it's way too late to ask to modify the installer, so that it 
    warns the user if "old" envir vars are set, 

I don't think there is any practical way to distinguish "old" envvar
values from "new" ones.  We certainly cannot warn simply if any
TeX-related envvar is set at all.

    but I might suggest to make this warning really visible, on
    internet's doc:

It's already mentioned in some places.  It's a good idea to add it
everywhere we can think of -- can't hurt.

karl