Lot's of excuses why but simply we were a no-show. Our good friends (at least they were prior to us not attending) had to pay for our meals, drinks and explain our two empty spots at a table because we are idiots. I have asked forgiveness ( that is the very least we can do...) by email so far, they are still on their honeymoon.
It is such a horrible thing to do to people you like. Having been on the receiving end (when my daughter got married) I know how it feels to have people you might have not invited to save a space for someone important to you and then have them not show up. It's not the money (although that grinds at you) it is the complete lack of respect and recognition that their day was not of enough importance to you; to at least show up.
Yes, I feel guilty and I should. Don't do it to other people. Be ready because it is going to happen to you. Call the folks on your list, send a reminder email. Maybe we should all have two "save the date" cards. One in the beginning and one at the end. Ironically the closer the bride/family gets to the date, the more important and all encompassing the date becomes. For your guests though it can be a date they reserved a very long time ago and one that with each day is farther from their memory.
At least that is part of the excuse I have going. Don't invite me to your wedding... I might not show up.
