Aircraft emergency oxygen: how hard do I pull on the mask? AKA 'why is the safety briefing/training inadequate'.  I tried Googling my title and got lots of sites explaining the emergency oxygen systems, procedures etc. that I already mostly knew.  The briefing: 'Pull sharply on the tube to start the flow of oxygen' is not exactly fully informative or reassuring.  The things look so fragile that it must be fairly easy to rip the tube away from the oxygen generator/supply bus pipe/whatever.

How am I supposed to know how hard to pull?  Is there some sort of click/detent that can be felt as I pull on the tube that indicates 'OK, you've turned the oxygen on'?

Could not a simple mechanical flag indicate oxygen on, eg 'Pull on the tube until the indicator flag turns green', or the like?
When they first fall down they'll be too high to reach your head, pulling on them will release a switch to activate the generator and release enough slack in the line to reach down to your chest comfortably (for children).

Some types are suspended by a cord connected to the switch:


(image source: wikipedia)

Then you will just need to pull until the cord disconnects from the ceiling.