If I correctly recall, Gemarrah Brachot states that the Chatan is exempt from davening at the time of the chasseneh (or is this specifically for Ma'ariv)?
I have heard of several situations where the wedding was scheduled close to but just before twilight, so the ketubah was written for a specific date. At the last minute, the people at the chosson's tisch insisted on davening mincha. When mincha ended, it was already twilight and they had to wait until nightfall and rewrite the date on the ketubah to the next day. The delay caused inconvenience to all the other waiting guests and really infuriated the hosts who had to pay overtime to the caterer and the musicians. This doesn't sound right to me. Is there an absolute requirement that mincha must be done at the tisch, or couldn't people have assembled a minyan in another room without involving the chosson and their family?