Collective nouns can be tricky because what is implied by it matters. If that collective is acting as one unit, then it is referred to as being one. If it is acting as individual members inside that unit, it is referred to as being many.
I see people who try to be proper get this wrong all the time. I read Slashdot often, and many people (from America) on there seem to make this mistake. When referring to a company name, they seem to like to say "are", when they should say "is". Example- "AMD is releasing a new chip" is the correct way to say it. They like to say, "AMD are releasing a new chip". This is wrong.