I believe unless you are officially a sponsor for the games, or have recieved permission to use branding, you may not use the phrases "2012 Olympics", "Olympic Games" or "London 2012". There was a hotel had to change it's advertising to "Need rooms for the big event this summer" or something allong the lines because they weren't an official sponsor. And a Cafe had to change it's name from "Cafe Olympic" to "Cafe Lympic" [1]
From the 2012 Olympics "Using The Brand FAQ" [2]
>4. Who is allowed to use the Games' Marks?
Official commercial partners, sponsors, suppliers and licensees are allowed to use the Games' Marks in accordance with the terms of their agreements with LOCOG or the IOC. See our current partners.
>
>We have also granted a number of non-commercial partners helping to deliver the Games the right to use our brand. This includes central government departments, the Greater London Authority and boroughs hosting various events for the Games.
So it's more likely than anything they were taken down just for using the Olympic name and modified logo
[1] http://www.businessweek.com/ap/2012-05/D9UTL52G0.htm
[2] http://www.london2012.com/about-us/our-brand/using-the-brand...