The only one that leaks when I fill it is the Vector. It leaks a little when it's almost full. If I don't get the tip square on the lighter fill valve I do get a shot of spray back at times. But for the most part I don't have any trouble without the tips. I read somewhere that most lighters don't need the tips.
I've never used the tips either. Once in a while I'll get a little spray but its never been a big deal. If I had an ST Dupont I might be worried about messing up the valve, but then I would probably be using their fuel with their tip anyway.