Well, my uncle (plumber) told me there's nothing bad with the match-technique as long as you try it instantly after turning on the gas!
There won't be enough gas-air mix for an explosion, just a very tiny flame. Gas doesn't have that much pressure. I've seen him try that after repairing our kitchen stove.
He also took apart our main gas valve live to fix it (it was leaking and there was a pressure test scheduled). He couldn't really turn off the gas for all apartments, so he decided to do it live. He handed my dad a wet rag and told him to push it into the opening... didn't even smell too bad. And if there had been significant amounts of gas in the air it would have smelled!!!
