## copying with .SD / .SDcols  causes issues
ven.cols.using <- c("venue", "city", "state", "country", "netCap")
venues <- CAconcerts[, .SD, .SDcols=ven.cols.using]
venues[, new.column := 0]

   # --- however... if wrapping in copy()--- #


venues <- copy(CAconcerts[, .SD, .SDcols=ven.cols.using])
venues[, new.column := 0]