The reason your cruise was not enjoyable was that you spent so much time making note of how many times the ship personnel talked or acknowledged your mother instead of you.

You could have opened the conversations with comments such as "...yes, mom and I are enjoying the cruise so much..." or "...now that you have my mothers order I would like to order a drink also..."
There were many occasions when you could have made yourself visible and chose not to.

I am not excusing their behavior regarding this, I am only saying that you can only remain invisible if you choose to.