I'm implementing The Secret Weapon and have been on it for about a week now. I just deleted my 1-Now tag by accident - I thought I was deleting a note and I blew by the warning message. Luckily, I'm very busy with one project right now so there weren't many 1-Now items in my list so I was able to recreate it but, for 10 seconds, I was in complete and utter panic .
I've also had the problem of partially entered tags creating a new tag - like '1' instead of 1-Now. This breaks my flow. "Mind like water" requires that you concentrate on one thing completely - and that's what I was hoping The Secret Weapon w/ Evernote would help me do. However, if I have to worry about trusing the software I use (or my ability to use it) for my 'trusted system' then I cannot use it.
I vote for a lock feature on tags (and would upgrade to a paid account if it were added). Thanks Luckman212 for your work on this issue.