If Odoo can define such restrictions on the enterprise modules (CAN NOT BE published, distributed, sublicensed or sold  - doing so is a violation of the license agreement. ) then it means that any other companies can do exactly the same. 

like in this case, developer can rebrand the POS and start selling it to the customers delivering two links. one that points to Odoo community LGPL license and another one pointing to his own licensing agreement which can pose ANY restrictions similar to what Odoo is doing. 

However, If developer wants, He can even sell this POS as a service and using this method, he doesn't even need to worry about releasing his customisation source code to the client. If customer claims that you are using LGPL software and I demand the source code, He can point to github.com/odoo.

Odoo Community is 100% Open Source via LGP3.

Odoo Enterprise (also available via the Online edition) is licensed with several restrictions - code from that Edition that CAN NOT BE published, distributed, sublicensed or sold  - doing so is a violation of the license agreement.

Odoo will vigorously defend violations of the license agreement for the Enterprise Edition, but as far as the Community Edition is concerned - you are free to modify and re-publish it, provided the fork is also licensed in the same way (LGPL3).  The code is still copyrighted as before.

https://www.odoo.com/documentation/user/11.0/legal/licenses/licenses.html

Odoo Community code that is licensed via LGPL3 is at https://github.com/odoo/odoo

Notice the fork button is available on that page: