I doubt there's any laws against smoking in queue lines. On the other hand, I have no doubt that smoking on the rides is illegal.
Now, you say they'll save $20,000 by not having the eco people have to clean up cigarettes all day long? May be true, but I bet they loose more by security having to take care of violators (labor) and people who would choose not go to the park because they don't have the "freedom" to smoke. I mean, I do know of people who avoid certain venus because they can't stand the smoke, but PKI is an ourdoor place, so I doubt they'll necessarily bring more people in with this. So long as they have designated smoking areas in convenient places throughout the park, it should all work out.