CLS,
Airlines don't muck with them!! The only reason a door is designed to disarm when opened from the outside is for a very simple reason. The last thing emergency services want is to open a door and get a slide deploying into their face.
The airlines have a good policy as it is now! On not every aircraft the slide disarm when the door is operated from the outside, 727/737. So for an airline that operates a mixed fleet it is better to have one policy for the whole fleet to avoid confusion.
msexyjet,
I am sorry but i don't agree with your explanation that it could have happened because the crew memeber was tired. If you feel that you are not able to do a proper job because the company makes you work to hard then their are only two choices: call in sick or leave to another airline.