I have shared air 3 times. Two of those, the guy may have been able to make it back but the last one was really an out of air.
As a side note, do not feel peer pressure not to be the one to shorten everyones dive. If you dive with a guy who uses less gas and are afraid to turn the dive, you will run out of air. Period.
Also had my buddy cut me out of mono net once. A good buddy is priceless.
Check the close calls section of the accidents forum. More than a few are about buddy saves.
As a side note, do not feel peer pressure not to be the one to shorten everyones dive. If you dive with a guy who uses less gas and are afraid to turn the dive, you will run out of air. Period.
Also had my buddy cut me out of mono net once. A good buddy is priceless.
Check the close calls section of the accidents forum. More than a few are about buddy saves.