DON'T CUT IT OFF!!!
I struggled with this same dilemma for a few years until I found the Super Deluxe Boom Mount. Go to tachyonmotorsports.com and check it out. Yeah, I know it sounds pretty tacky (no pun intended)

With that thing installed, I can have my boom and extended pylon up at the same time and still use the factory pylon for a slalom set without taking either of them off. It's pretty cool. I also have it mounted high up on my pylon above the boom clamp so the slip-over extended pylon that I have actually sits about 30" off the floor. It gives the extended pylon that much extra height over what it normally would be (slipping over the factory pylon) and much more sturdy besides.
The only problem I have with it is that it just doesn't look that good. Not that it's terribly ugly. In fact, the fit and finish is superb. It just doesn't look "right" on the pylon. It would probably be much better if it was anodized black to go with the black pylon. It is stronger than s**t though and if you remove it you would never know it was ever installed. I keep mine installed permanently just like my boom clamp and I really don't get a lot of "Hey, what the hell is that thing"? But then again, most people I go skiing with know what it is. After you have it on you definitely get used to it and now I don't even hardly notice it. In fact, most people riding with me find it really handy as an extra high hand grab if we hit other wakes or rough water. Since I installed it I also have yet bang my knee on the boom clamp because this thing is in the way and youcan't help but see it. So that's actually and added benefit that I'm sure was never thought of in the design process.
They're kinda pricey (I think I got mine for $100 several years ago) but they work wonderfully. If you want I can get a pic but there several on their website. I could get one of how I have it installed if you want though. Just let me know.
Hope this helps.