I'm also relied upon by Rt-H for experimental design assistance. Reading over a protocol, I found an error that would result in a fatal flaw in the design. After pointing this out to her and the students, there was a big email flurry to solve the issue. Since I am not the students doing the experiments, or the advisor I was not in on the solution. It took me two days to track down a student and get the story on the outcome.
These things are just small annoyances really, but they make it clear that my position in the lab is very well, un-clear. Defining my place in the lab by all these things that I am not has got me me wondering exactly what I am in the lab...On a related note. Geez, grad students take up a lot of time!