I was in a wedding for a sister in August and the bride and groom decided that when it came to inviting their group of friends unless you've been dating someone for a very long time you were did not get an "and guest" invite. I wasnt seeing anyone at the time and so since all the single people can solo it was so much fun! There were definitely matches made during the course of the reception
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But I think that some people feel the need to bring dates if they think they need to show off. Especially if there is a former fling there or someone they want to upstage some will go rush out to find a date. People sometimes forget that the point of a wedding is to celebrate the couple not try and get yourself in the spotlight for coming with a good looking date.