Capt Pit Bull
My checklist tells me to put the TCAS to TA/RA only when cleared to line up or take-off, so hopefully we should not have twelve a/c all ACASing away at the holding point ( assuming all operators use the same system). Out of interest, what does your checklist say?
And my Ops Manual requires me to check the TCAS in LVP's before lining up. I accept that the absence of returns does not guarantee empty airspace, but it all helps SA.
Cheers, TP