The Department of Transportation fined several smaller online travel agencies upwards of $50,000 for failing to disclose on their websites that flights they were selling were actually codeshares operated by other airlines. In other words, a flight would be displayed as, for example, United Airlines, but it would be operated by US Airways.
This issue came to a head when a Continental Express flight, operated by Colgan Air, crashed a few years back. Questions arose as to whether codeshare partners (especially “express” partners) were being held to the same safety standards as mainline carriers. The DoT required travel agents to disclose when a flight was being operated by a codeshare partner.
For what it’s worth, the OTAs blame the GDSs for not providing full information about whether a flight was operated by a codeshare partner. This is one reason why I generally recommend sticking with a well-known online travel agency if you feel compelled to book through a 3rd party. I’ve found repeatedly that the smaller OTAs do not provide full fare, tax, fee, and codeshare information until either late in the purchase process (or not at all).
OTAs affected by the ruling include Cheapoair.com and AirGorilla.com. Generally, the DoT drops the fines if the OTAs comply with the regulations for a year.