In Krakow one year there was a poor orphan girl who was getting married on a Friday, Her brother owned some seat in the shul and this seat was supposed to be some sort of dowry for her new husband.
On the Friday of the wedding, a dispute arouse over the dowery and it got late in the day into Shabbos. The dispute finally went to the Rema.
The Rema made his decsion, but it was Shabbos. The Rema poskined that the wedding should occur on SHABBOS and he perfomed the ceremony himself to make it clear it was ok. He did not want a poor orphan girl to feel her wedding was any less than anyone else.
However this decsion was not popular among other. Since the Rema himself performed the wedding they allowed this one to happen, but to prevent this from happening in the future they said no more Friday weddings