"is the keyword "mozilla1.x" still used or has this been replace by the flags"
Keywords are no longer used for these purposes.
"is it possible to change bugzilla so that only drivers have the permissoin to set it as "+" or "-" to avoid mistakes/confusions?"
Anything is possible with bugzilla if someone's willing to write the code. But why waste coding resources on something that people can easily learn? You're not setting review on patches, are you? You're not setting developers' priorities or target milestones. It shouldn't be hard to learn to not set the + on a flag unless, like making any of those other changes, you're qualified to do so. Like any feature in bugzilla, if you're not sure how to use it then ask before changing things. You can ask in newsgroups, on mozillaZine, in bugs themselves (although for issues not specific to a single bug this is discouraged), or in an email to me. But when in doubt don't make changes to any fields in Bugzilla. Ask someone first.
--Asa
"Keywords are no longer used for these purposes."
in that case, would it not be a good idea to remove the keywords - at least the mozilla1.3 and mozilla1.4 keywords - so people don't waste time using them.
"It shouldn't be hard to learn to not set the + on a flag unless ... you're qualified to do so"
hmm... that seems to be placing rather a lot of faith in people's willingness to be bothered learning. educating thousands of clueless users by correcting their mistakes may well be more effort than writing the code to prevent them from doing so... but I guess it will become apparent how much of a problem it is (or is not)
Guide to the New Bugzilla Flags Used by drivers@mozilla.org