C4C - Contact permission field

Dear Experts,

I have a question regarding the functionality of the field Contact permission, which can be found on the left sidebar in contacts, account and individual customer. I did some tests on this and noticed that when the field is set to ‘Disallowed’, I could not send any emails from a ticket to this account. Is there any other impact on the system? Further what does the system do, when the field is set to ‘Check permission’? Which permission does it relate to? And how does it relate to the Marketing permission settings?

BG,

Bart