Yes, I have done this even with a tip down knife by catching the stumb stud on the reinforcing of the top of the pocket of a pair of jeans. I think wave is a certain design feature in some of the emerson folders which I think are tip up. It doesn't work well on all pants or fabrics or all carry positions. Some people call it a draw opening, and there was one guy, w. Hock hocheim I think, that advocated a partial opening during a draw leading to a slash, using the slash to finish opening the blade. There is the reason I only watched one of his videos. I'm sure he's a cool guy, just not my style. The draw opening has always seemed to me to be something that was cool to do and show people as you were opening a box or letter, but back when I was really into knives as toys, I tried and tried this and got ok at it, but I also threw several knives across a room or nearly into my foot or eye or through a window or well you get the picture.
Basically, I'm just curious as to which people think is faster, easier, safer, etc. I kind of have my own complicated opinion which can be summed up as it depends on the knife, the user, and the carry method including the type of clothing and holstering point. I just like getting other perspectives on the matter. Thanks for the responses, and Prof, I didn't see your response until after I had typed the above so, aparrently well informed minds think alike.