I've always wondered this because I hear of plenty of people getting offered to be bumped off elal flights but whenever I ask at the check in desks, the check in assistants look at me in a funny way! Is this the wrong way to go about this? Is there a technique?

Also, on my outward flight to tlv two weeks ago, i was travelling alone, and a friend of mine who was also traveling alone got automatically upgraded to business?

My question is, how do you get bumped off/upgraded? Is it pure luck or are there other factors involved?