Well, is it any less of a spoiler if you come across it in a different place from where you might expect a spoiler?
I am planning on watching that episode of Enterprise this evening, so you've given me a little spoiler. Doesn't really bother me too much, but some people really really really hate them, and I find it is always best to err on the side of caution - I don't want to inadvertently ruin someone's enjoyment of a show.
I think the important factor is really that it is a brand new ep that only North Americans would have had the chance to see so far - and there are quite a lot of Enterprise fans in other parts of the world!