what is the use of access given to Contract Party roles and how its work ?

Summary: In the Contract we have assign the Contract party Contact role and there is option to select how much access you can give to a role such as 1) Full, 2) No access, and 3) Read Only. We have given the access to the role as "read only or No access " and still that role can make changes in that same contract. So our question is that how the Access giving to contract party roles works.

Content (required):

Version (include the version you are using, if applicable):

Code Snippet (add any code snippets that support your topic, if applicable):