The documentation states:

You can only specify time estimates and log work on an issue if your JIRA administrator has granted you the Work On Issues permission in the project to which the issue belongs. Note: Anyone with the Browse Project permission can view an issue's time tracking information.

Ref: https://confluence.atlassian.com/display/JIRA060/Logging+Work+on+an+Issue

Observed Behaviour: If a user that does not have the "Work On Issues" permission (confirmed with Permission Helper) creates an issue, they are able to see the Time Tracking field, in other words they are able to enter an Original Estimate.

Expected Behaviour: JIRA should match what the documentation describes. If the "Work On Issues" permission is not associated with a particular person, that person should not be able to enter an Original Estimate when creating an issue.