In most of europe the anthem is only sung during national games e.g france v scotland match.

If it was a big game with teams like manchester v barcelona theyd treat it like a national and play the anthems of what country they operate out of, also if it was like the english premiership etc they may play the anthem, they certainly do at the final.

Friendlys and normal games typically the answer is no, only for very significant matches.

In scotland we only really sing for national games, but not the uk anthem, thats regarded as englands due to 1, most scots dislike the monarchy and 2, that anthem originaly had the line crush all rebelious scotts, didnt go down well.

From a european perspective, the usa seems somewhat obsesive, the anthem is played all the time, in sport, in assemblys, in plays etc, kinda overkill.
Oh and in scotland, generaly band plays and they let the stadium do the singing, except once when they had the guy who created flower of scotland singing it.
I dislike most instances of anyone making ANY song there own, typically, it sucks.

Well, your first question does not apply to me, since I live in the United States, so you already know my answer. But on the subject of "making it your own", I think I may have a different opinion than others. I think it's great. But I don't think it's so much that the artist wants to put their own spin on the song, so much as they adapt it for their specific talents. If someone with a very deep voice sings the national anthem, clearly they will have to change it to flow better, but it's not as clear for other singers that to make the song sound the best, they HAVE to change the way it is sung.

Besides, the United States' national anthem isn't actually a song, it's a poem, so anyone who "sings" it is reciting it incorrectly anyway.

I'm from Canada, yes it happens at most games.

It's form of religion I find. You're born on one side of an imaginary line so you sign hymns to an idol (flag).

I'm very indifferent to it.

In person, yeah I sing along with the National Anthem, but when I'm watching it on TV, I don't really sing with it. I don't really notice if they make the anthem "their own" but I might pay more attention on some.

No I don't usually go with the national anthem. If it's before a big game, then I usually just pray to god and keep it moving.