The so-called, "confirmed" leave ticket has always been a bumpable ticket-- it is just a non-rev ticket with higher boarding priority. Same thing for the ID50's that you or your parents/immediate family may purchase. This is why I would never bother purchasing ID50's for myself or immediate family-- there just isn't the value for the much higher cost. If you are flightdeck, just buy an ID90 for C or A class and the boarding priority should trump any Y-class standbys if airplane fills up (and take your chances, save the money).
The exception is the ID50's for your Nominees-- they are not to bumpable (although some gate agents may not realize that). So it has been explained to me.
Now if leave ticket holders get bumped while Space-Available ticket holders ride, we have a real issue.