Has anyone ever been invited to a wedding (in game I mean lol)?

My sims will sometimes get those phone calls from NPCs saying they "found a ring" and "should they say yes", and sometimes my sim will say they should and then they will be engaged. ANd because I have wedding stories my sim can then "ask to be [their] sim of honor" or for an invitation to the wedding but...NPCs aren't ever going to get married on their own or host a wedding are they? Without mods I mean. 

I'm just wondering if I'm wrong about that, and if anyone has ever seen engaged NPCs actually tie the knot, or even get invited to an NPC wedding. Cause if not...I'm a little confused what they point of all that other stuff really is lol.