Ours will sometimes roll in the dust while wearing her harness, and sometimes in mysterious substances that we'd prefer not to think about at the base of the communal mailbox. We've learned not to let her get too far into bushes.
It's really kind of time consuming. She has to sniff every bush, nibble at every blade of grass. Once in a while she'll get a wild look in her eye and sprint up the nearest tree, then we have to make sure she doesn't go too far up or get the leash tangled in branches. On the whole, though, it's worth the patience required as she gets to get outside and do cat things without us worrying about her.