Once you have purchased a Dynamic stamp, you may be able to secure it within the document to assure no alterations after placement.
This may be accomplished by implementing the following:
After insertion of your Dynamic stamp into a document, go to the Tools section.
Choose Protection>Encrypt with Password.
The screen will likely look something like this:
Under the Permissions section, near the bottom, check the box 'Restrict editing and printing of the document. A password will be required in order to change these permission settings. Choose a password. Choose whether printing will be allowed. Choose whether changes will be allowed. Click ok and save the document.
Now, open the document and perform a test. Try to choose the stamp to move it, delete it, or edit it. It should not allow any of these to occur.