Ceremony seating- blankets?

This is a HUGE no for me. I would not care how ugly the chairs are, I would take a chair over sitting on a blanket any day. My spine is fused and I literally am not physically capable of sitting on the ground. (If you didn't know me well, you would not know this about me.) If we arrived somewhere and realized that was the plan, we'd likely leave. Even without physical issues, if someone expected me to sit on a picnic blanket -- say for a 4th of July picnic -- I'd be wearing shorts & a t-shirt, not the sundress I'd likely wear to what I expected to be a casual wedding.

You asked for "honest opinions" and mine is use the chairs! Besides, I'm not guessing mis-matched blankets & sheets look a lot better than blue chairs....

Also, if someone you know finally told you they think this is "stupid," listen to them! It's likely other guests who have heard about your plan thought the same thing and either didn't want to hurt your feelings and/or figured you'd realize what a bad idea this is on your own. It sounds like someone finally figured time was getting short and they had to speak up. It would still be a bad idea if the venue had no chairs and you couldn't afford to rent them, but not using chairs because you think they are "ugly" would really tick me off as a guest.... REALLY??? Your aesthetics/tastes are more important than letting the venue provide me with a chair they HAVE on site????

ETD: The things you'll often see cited on WW regarding what is minimally REQUIRED to host guests are: food, beverage, protection from weather, and a "chair for every butt". Based on what you've shared, your current plan is people sitting in full sun on the ground -- you're potentially missing two of the four essentials. I'd try to fix what you can in the time left. Good luck!

Honestly, if I showed up at a wedding and this was the set up, I would probably be really upset. I am pretty laid back, but I have some pretty bad arthritis in my back and this would guarantee a night of pain for me (I'm sure most people wouldn't know that about me because I work out and do all sorts of physical stuff). I hate that I have that issue, but I do. I would at least want a head's up so I could bring the ugly chair that I take to Shakespeare in the Park with me. I do think the blankets are a cute idea, but I would want the majority of guests to have a choice whether or not to use them. If it were me, I would offer the chairs for the ceremony and then set up blanket picnic areas that people can use during the reception if they want to.

I generally don't mind sitting on a blanket for the length of a ceremony, but in a dress it's just a big no. You have to stay in a certain position so everyone doesn't see your business and it gets super uncomfortable. Just use the chairs so you're not sacrificing guest comfort for your pictures.

Honestly, I'm pretty flexible if the couple is happy I tend to be happy after all it's your day. I like how it matches your picnic theme too. I've been to weddings where we all stood, why not sit on the grass. I think it's nice and unique However, if you haven't already you may want to find a way for people to know it's coming so they don't show up in an outfit that isn't good for sitting, or make it known that your wedding is casual so people can feel comfortable to not where dresses/skirts.

I would not sit on the ground. If there was no place available to sit, I would stand up wherever there was a spot. This is a case of letting your vision overrule basic comfort of your guests.