It’s a completely different thing from etiquette because it’s a custom that has been around for awhile that doesn’t offend anyone and create awkwardness if you choose not to participate. Usually it’s something people have done so long they can’t tell you why but it’s not missed if it’s not there most of the time.
For example:We are planning to skip the MC along with announcements and toasts at the reception. Also skipping the bouquet/garter tosses, bridesmaid proposal boxes (new as of the last couple years at most so not old enough to be tradition yet), parent dances and participation. There might be others that can’t think of at the moment.