I had to leave my umbrella outside when it was pouring down a few matches ago. I protested that it wasn't a large golf umbrella,it was just a normal sized mans umbrella.
However, as the lady steward told me, it has a spike on the end of it, so could be used as a weapon.
So it had to stay outside in a pile of similarly prohibited brollies.
Fortunately it was still there when I came out after the game, albeit dripping wet after it rained all evening.
Fortunately the rain had stopped by then , and I used it as a walking aid on the way back home.