On the other hand... I just bought a monitor that Tigerdirect advertised as 22", but when it was delivered the box says 21.5", and I don't think that's really worth paying my lawyer $250/hr to handle.
It's common practice for monitors to be advertised by class and not actual screen size (such as 22" Class LED Monitor, or a 50" TV measuring 49.5"). It is not common practice (and wrong) for 1080p video to mean "720p" - those are distinct values. The video "class" is HD, but specific "size" is 1080p or 720p.