Do you have the equivalent?

There will me many Australians who'll have no idea who Tim Tebow is or that it's possible to Tebow.
There would be plenty of Aussies who will never seen The Hills and thus be ignorant of the life and trials of Heidi Montag.

But I assume many people outside Australia will have no idea who Jason Stevens is or the book he wrote.
Thankfully, very (very!) few people outside New South Wales will have ever endured an episode of The Shire or Being Lara Bingle.

Yet, depending which country you live, you can make the same point by interchanging the American version for the Australian equivalent.

In fact, I've sat in numerous conferences where a local equivalent exists for the point they are trying to make, but the speaker has stuck with their familiar line of thought.

So, who is a fault, the host or the speaker???

In some cases there's a fairly easy remedy which the speaker has overlooked. If the speaker knows that they are going to use a personality who is culturally specific, and will thus need to be explained, then I feel it is up to the speaker to enquire if there is an equivalent which the audience will be familiar.

But, if the person who has invited the speaker is aware of the general gist of the talk (like if they are speaking about a book), then I also think a degree of responsibly falls into their lap. If the host is fairly certain that the speaker will refer to Tim Tebow in front of an Australian audience, then they might want to helpfully suggest a fitting alternative.

So... who is at fault?
Depending on the situation, potentially both the host and the speaker.

Either way, it is the audience who can be the losers.