Possibly be happier if the horse is unshod - I wouldn’t ride a shod horse on anything icy .... but it really is a matter of judgement as to how solid and reliable your horse is and whether there is any give in the ground!
He is shod all round. I expected the field to have thawed more than it had. Track down to it had a few icey patches but they were avoidable. But got in field and it was still frozen. I wasnt sure if to turn round and risk bouncyness or carry on round field. Hes pretty well behaved so compromised and walked round half of it.
I would, but it's very much a judgement call depending on the horse and the field - if it felt slippy I might decide it's not worth it, but I've never really worried about frozen grass other than the hardness/ rut issue.