The new wedding crasher isn't interested in the open bar and passed hors d'oeuvres at your cocktail hour. Or even the pile of envelopes on the gift table.
Amid rising hotel rates, crashers are after your discount.
"Anecdotally, it's becoming an increasing problem," said Bjorn Hanson, divisional dean and clinical professor for New York University's Preston Robert Tisch Center for Hospitality, Tourism and Sports Management.
Getting in on the lower price connected with a block of rooms for a wedding or a corporate event is becoming more appealing as hotels recover from recessionary lows.
(Read more: Most Outrageous Weddings)
The average U.S. daily room rate for 2013 is expected to reach $110.65, up 4.2 percent from last year, according to PKF Hospitality Research. And rates are steeper during high-demand times such as wedding season or a busy convention period, said Robert Mandelbaum, PDF's director of research information services.