The law of untended consequences soon may be applied to the Lawrence City Commission’s decision to ban smoking in most public places in the city.

Predictably, the decision has launched a flood of plans from restaurants and drinking establishments for new outdoor seating and dining areas to accommodate smoking customers. In some locations, this may be a reasonable strategy — although it would be too bad if moving the smoking section to the patio made it impossible for people who wanted to avoid smoke also to enjoy outdoor dining in nice weather. In other areas, however, it could have some undesirable effects.

One of those places is downtown Lawrence. City ordinances currently allow restaurants that do at least 70 percent of their business in food to have sidewalk eating areas. These eating areas have been a popular addition in recent years and likely will become more popular with the smoking ban.

Although eating outside is a pleasant diversion on a nice day, these sidewalk cafes have some drawbacks, notably that they use up about half of the available sidewalk and sometimes create a bottleneck for pedestrians. That problem would be increased if more restaurants get approval for sidewalk seating. If sidewalk seating is used primarily as a way to accommodate smoking customers, new issues arise.

The goal of people supporting the local smoking ban probably wasn’t to have the sidewalks of Massachusetts Street lined with people who had stepped outside for a smoke. Neither would they want to have to walk through a cloud of smoke to enter their favorite restaurants.

California has had a smoking ban similar to the one approved for Lawrence for a number of years. A resident of that state predicted this problem in a letter to the J-W editor some time ago. Although he supported the smoking ban, he disliked having to pass through the phalanx of smokers that now seemed to gather outside almost every place of business.

Not only will city officials have to deal with requests from restaurants, but owners of bars that do less than 70 percent of their business in food also have indicated they plan to seek approval for new outdoor seating areas. It’s only fair, said one owner, for the city to help the bars minimize the damage they expect the smoking ban to cause to their businesses. Already one downtown bar owner reportedly has started work on an outdoor seating area without gaining the proper city permits.

The city can’t tolerate such unauthorized projects. Commissioners may not have foreseen a proliferation of outdoor seating requests, but they now will have to deal with it. As they draw the lines, they must be fair to businesses, but they also must consider the overall impact their actions will have in certain areas, especially downtown.