I don't. I have better things to do than babysit various accounts I've signed up over the years. Just because someone signs up for an account and forgets about it is not a good enough reason to have my information DESTROYED WITHOUT MY PERMISSION if I do happen to be busy that week to sign in somewhere to accept a legal disclaimer.
It’s only ‘{one|that} week’ from today. The people that hold your personal data appear to have not planned in advance. Why should people (“data processors”) have the right to forward your personal contact details in perpetuity? Isn’t that a problem? They don’t need to ask permission to use those details for purposes for which you’ve already granted permission.
GDPR is touted as a policy to tackle the issue of the larger players abusing their market positions and our trust; instead, so far, my lack of response would just ensure that I am unsubscribed from my alumni association in the UK; what good does it do to me?!
This may be a misunderstanding, or a cautious approach, from your alma mater. If you’ve given them permission for them to hold your data about their activities all is well. Many companies are choosing this as an opportunity to confirm that permission for the sake of future legal argument. Rob