Steps to reproduce the issue

User Profile Plugin, select "Required" on "Terms of Service" option and select any article in "article Terms of service"
Create a new user thru frontend menu, leave "no" in "accept the tos", the new user is still created

Expected result

Should display an error message:
Please read the Terms of Service. You will not be able to register if you do not agree with them.

Actual result

No error message, user is created

System information (as much as possible)

Joomla 3.5.1/php 7/ mysql 5.7

Additional comments

To correct this, the line 376 of the file plugins/user/profile/profile.php should contain
if (($task == 'register') && ($tosenabled) && ($tosarticle) && ($option == 'com_users'))
instead of
if (($task == 'register') && ($tosenabled) && ($tosarticle) && ($option == 'com_user'))