I'll wager that you'll be good.

You can get most of the effect by never shifting into the big ring (or, if you want, adjust the outer limit screw to prevent you from shifting to it accidentally).

The big gap between the big ring and middle ring, size-wise, is what will help keep your pant leg out. You do run the risk of having it get caught between the FD cage and the chainring, though.

If you go with a bashguard, it might not hurt to try using one that's one or two sizes bigger. I'm looking at the crank on my wife's Townie and the plastic pant guard looks like it extends half an inch past the big ring.