Cancelling day out due to behaviour

She sounds so over tired or coming down with an illness.
Have a calm day. No screens and left in room without bright light for a rest with her best toys.

If she calms down enough to say a proper sorry, I would take her.
She could also have been over anxious at the thought of the outing.

I wouldn’t, although I’d be upset, I’d try and give her some 1-2-1 time. Have a chat about her behaviour, she might be able to tell you something enlightening about what happened. I would let her know that if she behaves like that again she will lose privileges. I do think children need to be aware of consequences for them to be useful deterrents.

I think you need the trip out to reset and move on.
A meltdown is not the same as just being stroppy. Help her talk through her feelings and find her a better way to express when she's so angry and upset.

I don't think either of you are going to enjoy a treat out after that floor show. She has hit you and been destructive. That should be an instant loss of privileges.
Talk to her when she is calm and get an apology and tomorrow is another day, but no treats.

I would never punish for a meltdown. She might really benefit from some calm 1:1 time too.

I personally think when a child is generally very good (which is what you've said here), when they act relatively out of character, they should be shown some grace. In my experience, there is usually a reason behind things like this if it's not the norm and it's not always immediately apparent. She could be over tired for some reason, or in the beginnings of coming down with something for example.

Either way, if this it's rare for her to behave this way, I'd let her calm down, offer her some comfort, explain destroying her garland wasn't acceptable and that she's not to take her anger out on things and damage them and tell her a better way of being angry. Then I'd draw a line under it and stick to your original plans.

I think a different approach is needed if this became a frequent thing, but even then I think the key thing is to teach and guide on better ways of expressing feelings rather than just punishing, without trying to teach.

Have a similar age dd and at that age it can be hard for them to regulate their emotions especially if they are tired or have routine changes like over school holidays. I tend to go by how she reacts after a meltdown like this, if she’s sorry and behaves well then we carry on with plans, if she doesn’t listen, isn’t sorry and behaviour doesn’t improve then we cancel plans or go home if out.

I am all for cancelling treats for bad behaviour but this sounds like it was a little out of her control. I’d have a conversation with her when she is calmer. Ask her why she was so angry and make it clear that it isn’t right to destroy things even when you’re in a temper. Tell her she needs to earn the cinema trip, give her a couple of jobs to do to earn the trip back. So you are rewarding positive behaviour, not the poor behaviour of this morning.