Restrict Attachments by Issue Type

[Kristin Lyons]

We are looking to restrict users from adding attachments to a specific issue type unless they are added to a custom user picker field.  One restriction we have is the issue type is on multiple projects and all other issue types should behave normally (anyone can add attachments).  I have seen one solution where we could add an attachment initially and then a ScriptRunner listener would verify if it was added by the specific user and if not it would delete the attachment, but that won't work for our use case. 

Are there any plugins or other options we could use?

[Matt Doar _Adaptavist_]

What about a ScriptRunner behaviour or fragment to conditionally hide the Add Attachment functionality? I couldn't find example code though