To put it into perspective, the London Marathon handed out 760,000 plastic bottles of water.
I'm well aware, it doesn't make it better. Plastic doesn't not have infinite recycling possibilities and so ends up on the landfill after 2 or 3 uses, where essentially, it stays on the planet forever as after hundreds of years it turns into microplastic.
What material do you want them to use?
Um, why do they need to provide any bottles? It's a wedding, not a sport.