Okay, I have an update: If you register an account on NW, you can still play even if you don't get your activation emails, and it will still track your stats. I just registered an account yesterday and played on JO and saw it was tracking my stats on NW. You can add in CD-Keys of other games you want to play in the game itself so that is not an issue. This is a relief
Of course, I bet people will still do what I did: get worried and not even try to play the games until their email comes. Perhaps an announcement should be made on the NW2 forums or NW about this? I hope this is all ironed out once NW2 is finished. It's been happening at least since august (based on peoples' posts about it) and it would be a shame to just abandon on their old games in favor of NW2.
However, without the activation email you cannot read / post on the forums, upload an avatar, or login on the NW site. Some features like pressing the "My Character" page in JO will complain you need to be logged in (when you already are), but that's no biggie.
On a side note: Does anyone know why the in-game stats page in Black Hawk Down was removed? I remember they did this some time ago. You can still read your BHD stats out-of-game, but it's just not the same. I think I understand why login was forced in BHD, so people can no longer play public games with a banned account, or cheat in public servers without risking their account being banned.