At the moment, if someone disables a test for an [orange] bug, they'll end up being set as the assignee, even though they are not normally going to be the ones working on fixing it.
These bugs typically end up with [orange][test disabled][leave open] in the whiteboard - however:
- in the case of say bug 798806, checking for [orange] wouldn't have helped.
- there are really too many variations on [test disabled] ([marked as random-if] and so on) to use that as an indicator
...so I suggest the easiest way is just to not set the assignee if the bug has [leave open] set.