Well whenever I'm working there I always get given instructions to not let anybody stand on the pit wall during test sessions, so they were naughty marshalls
Ermm the tunnel probably won't be open, even though it's appart from the building work. I might be wrong but I rarely see it open on test days.
Actually you might have some trouble spectating because of the building work. You'll most likely be limited to just the pit lane exit, but don't hold me to it!