An interesting insight into (I assume) US culture in the comments that I've certainly never come across before. Do restaurants really have their own proprietary versions of the "happy birthday" song over there? I've only ever heard the "proper" version in restaurants and other social gatherings here in the UK.
Wow, you learn something new every day. I didn't come across it the couple of times I've been over there. I suppose in TV and the movies we always hear the "correct" version (even in a public setting) because they've paid the money to Warner to be able to use it.