Hi Bigmig,
I'm curious if you've tried any monkeying with the PDF's after locking them up - found any ways to circumvent the DRM yet?
If you feel it's necessary to severely restrict access to these documents, then you are tacitly acknowledging that viewing them (even once) is a highly valuable activity, which you have made even more valuable by limiting the number of times they can do it. Scarcity affects the value of any resource.
I'll resort to a trivial example that may or may not apply to you, but it's not inconceivable that a recipient of the document could open a number of the files (incurring a count of 1) but before actually reading them, suffer a power outage or other distraction that prevents proper viewing or use of the content. That user could find this situation very frustrating, especially if the DRM was only going to allow viewing it once.
A skillful user - there is always a user more skillful than you are, no matter how good you are - may be able to find a way to break your DRM lock. By locking your document, you have increased the cost of the document to all of your customers, but this lock-breaking customer has now obtained a copy of your document that isn't locked. You didn't increase your rights, because you already had copyright over the document you created. Instead, have created a crooked business opportunity for that customer. You may have increased your legal opportunities to punish the copy-maker by locking the document, but you have to FIND them to punish them.
I may have run a little far with the scenario. As you can tell I think DRM is mostly annoying and sometimes has perverse side-effects.
No I'm not advocating doing something illegal. However, I take screen shots from my computer all the time. Why should it be illegal to do it when a certain combination of pixels is displayed, but not otherwise?
STF