When we go to a wedding, we arrive with the understanding that what we're seeing and experiencing was largely planned the way the couple wanted it.
Of course, planning a wedding is notoriously complicated so it's unlikely that everything quite went as envisioned. But if we're talking about a general design scheme or theme, we can bet that was their idea.
Of course, some couples can take their wedding planning prerogative a little too far, which you'll often hear about in stories of Bridezillas making ridiculous demands of their guests and particularly their wedding party.
But while those kind of nightmare weddings at least make it obvious where we should send our "regrets," some problems don't reveal themselves until we've already arrived.