I'm going to say it, as many times as I need to say it.
Tammy. Is. NOT. Bulletproof.
Her daykill can't be watched, nor tracked. That makes her kill a ninja-kill, since as d1 proved, she can keep the kills private.
Her daykill can't be blocked by a protective role. That makes her kill strongman, since it overcomes any protection a player may have.
Her kill can act as a governor, since if she, say, used it near the end of the day, it'd reset the votecount as shown already, meaning that anyone close to a lynch no longer is.
On top of that, you're suggesting she ALSO has BULLETPROOF protection? That'd make it so that Benmage would be the ONLY role that could find her. Otherwise, she'd cruise to victory--no lynching, since she's a day-killing machine and her dayvigs would be seen as dayvigs, not as day-SK-shots. No tracking, since she can't. No watching, since she can't. Benmage would be her one. and. ONLY. weakness, if she were bulletproof. That'd be the most souped-up SK I've ever seen, so bluntly,
Tammy's vulnerable to being nightkilled, and suggesting otherwise is ignoring basic balance, role mechanics, and in general, is just plain. simple. Fearmongering.