Should we give up our confetti exit when the venue bans even dried petals?

I sent the venue a picture of the dried petals Mum had bought. The reply was polite and definite: no confetti or petals anywhere in the courtyard.

Mum has filled sixty paper cones. She says the petals are biodegradable and can't understand why the venue treats them like something that needs cleaning up. I'm disappointed too; the exit photograph was one of the few staged moments I wanted.

We hadn't asked before she bought them. My partner wants to keep the cones for another occasion. Mum suggests using them just outside the gate, but we haven't checked whether that space belongs to the venue or whether we can use it.

Is there an alternative that still feels like a cheerful exit, rather than another group being told to stand and wave for the camera? I don't want to keep moving the idea a few metres until we find somewhere nobody has explicitly said no.