I did this when using the original double crankset that came with the Shogun 400 I recovered from a rubbish dump and converted into my fixed gear. I nipped off the teeth from the outer chainring, then filed them to a smooth, round finish, and that set-up has been on the bike ever since.

The real beauty of a bash-guard like we are discussing is threefold -- it reduces the risk of chainring tattoos, it allows you to wear long pants without have to put on cuff straps or stuff the cuffs into your socks, and it makes packing up a bike for travel a little cleaner and tidier because the chain is well protected.

The LX crankset I have on my Thorn touring bike also has a plastic guard on it, and I like it as much as the one on the fixed gear.