I would say no to havvianas!!
DH wore havvies!

I wore thongs, but only because MIL insisted I wear shoes... I didn't want to wear any. Then halfway through the ceremony, noticed that DH wasn't wearing his - and I nearly interrupted the whole thing to say "WHERE ARE YOUR SHOES?!?!" but thought it might be a little unclassy.
Tomorrow when I wear my wedding dress again (it's our anniversary!) I'll be wearing it with gladiator sandals! So go for it, and have an awesome day!