I received an invitation to join a slack group earlier today from a member of a college course that is coming to an end . I am not averse to staying in touch, but I am furious that my email has been distributed, presumably by the tutor, when I have not given permission. It is not within the college's policy.
Was still irritated about that - then an email popped up from a fellow choir member. Again, choir organisers have my details for admin purposes, not to share with an 80 strong choir.
I'm tempted to report both organisations the Information Commissioners' Office - the choir is a smallish organisation, but college is quite large, so should be fully informed about GDPR.