They are explicitly permitted. From Google's own statement on this (https://webmasters.googleblog.com/2016/08/helping-users-easily-access-content-on.html https:

They are explicitly permitted. From Google's own statement on this (https://webmasters.googleblog.com/2016/08/helping-users-easily-access-content-on.html https://webmasters.googleblog.com/2016/08/helping-users-easi...): "By contrast, here are some examples of techniques that, used responsibly, would not be affected by the new signal: Interstitials that appear to be in response to a legal obligation, such as for cookie usage or for age verification."