Did you reserve a hotel room because the wedding will be far away (more than a 2 hour drive), or for convenience? I would think that if the couple sent you a "save the date" card with hotel info *and* they know that you live far enough away that you would have to stay at a hotel, they intended to invite you to the wedding.

On the other hand, it's possible that since sending the save the date cards, the couple has had to reduce the guest list and you may have been left off. In this case, a phone call from the bride or groom would have been a nice gesture. But as Irulan said, a "save the date" is not a firm inviation, so they're not really obligated. (And hotel reservations can usually be canceled without penalty.)

How far off is the wedding? If I'm not mistaken, invites usually get sent out six weeks before the event. If it's more than six weeks away, I'd say wait a little longer.

If the six week mark has passed, I would suggest that you wait until you see the couple and give them the opportunity to bring up the subject themselves. Maybe they won't be able to invite you, but are planning to let you know in person. If they don't bring up the subject and you really think that this might have been an oversight or a case of a lost invitation, then try to talk to either the bride or groom (whomever is closest to you) in private so that you don't put them on the spot.

Hope this helps!

C.