When the PDF file is opened by user #1 with Adobe Reader or Adobe Acrobat it opens will full read-write permissions. When user #2 opens the file, it's also opened in the same state of read-write; there is no indication that another user has it opened with read-write.
This prevents being able to save changes to the document for either user. In similar products, such as Bluebeam, it will warn you that "another user has this file open, it will open in read-only mode". That ensures that user #2 is aware they cannot make changes, and user #1 is able to have read-write access for saving the file for changes.
@Arvind
When the PDF file is opened by user #1 with Adobe Reader or Adobe Acrobat it opens will full read-write permissions. When user #2 opens the file, it's also opened in the same state of read-write; there is no indication that another user has it opened with read-write.
This prevents being able to save changes to the document for either user. In similar products, such as Bluebeam, it will warn you that "another user has this file open, it will open in read-only mode". That ensures that user #2 is aware they cannot make changes, and user #1 is able to have read-write access for saving the file for changes.