The incidence of bad wedding related etiquette is growing amongst my friends. We just attended a DW where the rehearsal dinner had a cash bar - for both alcoholic and non-alcoholic beverages. Between fall of 2015 and fall of 2016 we have or will attend four weddings. Every single one has a cash registry of some form, and the two to come include a dress code. One is formal and one is semi-formal - I assume they will be high-school dance themed.
The internets is infected with bad ideas.