Had my front left door pop open last December with 3 PAX on board. Asked passenger on right seat to hold on to it and landed in a field close by.
I thoroughly checked the door and the mechanism involved for closing, and found it to be out of shape (stuff didn't seem in place) and it was difficult to close again. My first thought was the outside air temp which was below zero C at that time.
Back on base, everything worked like a charm again, and upon subsequent checking in the following weeks I've never found a problem again. Maybe the door wasn't latched correctly at the first place and that's what caused it to be out of shape a bit.
To be on the "safe side" I decided on a best way of handling such a situation when it would happen again, me alone without anybody who could hold on to it. Luckily it didn't happen again.
In any case, I'll probably never see these passengers again unless they are in for another adrenalin kick.
Makes me dream of a beautiful EC120 (= the Audi of light helicopters?) at night. I am not going to say what make the helicopter was but I guess you all know it. But reading these reports it seems it's a common problem and not type specific.