Common does not equal being acceptable and in good manners/proper etiquette!

You yourself said you hate it. Why would you do that to someone else? What did it make you feel like not having a seat. How will you feel if someone comes up to you complaining? What about the person that will remind you about it for years to come? We all know people that would actually do that!

Are the seated tables first come first serve or are you working on a seating chart?

If you are doing a seating chart the answer is pretty obvious who you whittle down off the invite list! If they aren't someone special enough you would assign a seat to IMO they can be cut down!

It sucks but like I said they will get over it and you'll have less to worry about the day of the wedding and less change of having some drama!