Why Contributor users can Share documents directly inside Office 365 (SP online) while on the on-premises the request will be sent to site owner

Question

I got confused on how the Share feature works in sharepoint online and on sharepoint on-premises.

now i thought that this rule is the based line for SP online and onpremises 2013:-

if a user does not have this permission "Manage Permissions - Create and change permission levels on the Web site and assign permissions to users and groups. " , then if the user chose to Share any thing then the share request need to be approved by the site admin

now from previous on-premises projects the above was valid. as i did these tests and they always work well.

1. If a contributor user (UserA) share a document with UserB, then the docuemnt will not have unique permission nor it will be shared with UserB, until the site collection approve the share request.

2. if i modify the built-in Contribute permission level, and i grant it this permission Manage Permissions, then when a contributor user share a document , then the document will automatically have unique permission + the shared user/s can access the document, and the site admin do not have to approve any thing.

Now today i was working on an office 365 project, i thought that the same rule will be applied.

1. so i checked the Contribute built-in permission level, and it does NOT have Manage Permissions as in the on-premises case. so i access the site using a Contributor user, and i share a document, i thought that a request will be sent to the site admin.. but what happened is that the document was shared with the intended users + the document had unique permission!! so seems on office 365 contributor users are more powerful than on-premises, and more powerful that what we expect.. as seems they can break document permissions and assign users to view/edit the document without having to get this approved by site admin.. so can anyone advice why this is happening ? is this how things suppose to work in SP online?

Answer 1

There is a sort of 'override' in both on-prem and online. If you go into Site Settings -> Site Permissions, under Access Request Settings, you can allow Contributors to Share items.

Two options are available:

• Allow members to share the site and individual files and folders.
• Allow members to invite others to the site members group, SharePoint Site Members. This setting must be enabled to let members share the site