The "sharing economy" – typified by companies like Airbnb or Uber, both of which now have market capitalizations in the billions – is the latest fashion craze among business writers. But in their exuberance over the next big thing, many boosters have overlooked the reality that this new business model is largely based on evading regulations and breaking the law.

For the uninitiated, Airbnb is an internet-based service that allows people to rent out spare rooms to strangers for short stays. Uber is an internet taxi service that allows tens of thousands of people to answer ride requests with their own cars. There are hundreds of other such services that involve the renting or selling of everything from power tools to used suits and wedding dresses.

The good thing about the sharing economy is that it facilitates the use of underutilized resources. There are millions of people with houses or apartments that have rooms sitting empty, and Airbnb allows them to profit from these empty rooms while allowing guests a place to stay at prices that are often far less than those charged by hotels. Uber offers prices that are competitive with standard taxi prices and their drivers are often much quicker and more reliable – and its drivers can drive as much or as little as they like, without making a commitment to standard shifts. Other services allow for items to be used productively that would otherwise be gathering dust.

But the downside of the sharing economy has gotten much less attention. Most cities and states both tax and regulate hotels, and the tourists who stay in hotels are usually an important source of tax revenue (since governments have long recognized that a modest hotel tax is not likely to discourage most visitors nor provoke the ire of constituents). But many of Airbnb's customers are not paying the taxes required under the law.

Airbnb can also raise issues of safety for its customers and nuisance for hosts' neighbors. Hotels are regularly inspected to ensure that they are not fire traps and that they don't pose other risks for visitors. Airbnb hosts face no such inspections – and their neighbors in condo, co-ops or apartment buildings may think they have the right not to be living next door to a hotel (which is one reason that cities have zoning restrictions).

Insofar as Airbnb is allowing people to evade taxes and regulations, the company is not a net plus to the economy and society – it is simply facilitating a bunch of rip-offs. Others in the economy will lose by bearing an additional tax burden or being forced to live next to an apartment unit with a never-ending parade of noisy visitors, just to cite two examples.

The same story may apply with Uber. Uber is currently in disputes with regulators over whether its cars meet the safety and insurance requirements imposed on standard taxis. Also, many cities impose some restrictions on the number of cabs in the hopes of ensuring a minimum level of earnings for drivers, but if Uber and related services (like Lyft) flood the market, they could harm all drivers' ability to earn even minimum wage.

This downside of the sharing needs to be taken seriously, but that doesn't mean the current tax and regulatory structure is perfect. Many existing regulations should be changed, as they were originally designed to serve narrow interests and/or have outlived their usefulness. But it doesn't make sense to essentially exempt entire classes of business from safety regulations or taxes just because they provide their services over the Internet.

Going forward, we need to ensure that the regulatory structure allows for real innovation, but doesn't make scam-facilitators into billionaires. For example, rooms rented under Airbnb should be subject to the same taxes as hotels and motels pay. Uber drivers and cars should have to meet the same standards and carry the same level of insurance as commercial taxi fleets.

If these services are still viable when operating on a level playing field they will be providing real value to the economy. As it stands, they are hugely rewarding a small number of people for finding a creative way to cheat the system.

