If I'm not mistaken, by having club membership you are then covered under the isurance of the club.
You'll probably find that a student/public must be a club member before they go flying with that club even if it is for one day.
When I go flying with friends they have to fill in a form, which makes them a member for that day only. Something to do with insurance, I've been told but can't unfortunately tell you the ins and out of it.
I'm sure there are others out there that'll know more.
Good luck
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Life is not BANANAS !