As mito pointed out, it was 18 volunteers conducting the first study ie assessing positionality. Not just using 18 young people, themselves playing some games or whatever you thought they were doing, The second study looked at 10 European teams over a period of 17 years. I’d say that gives a very good chance of coming to some decent conclusions. Team’s colours were determined a very long time ago, before money or advertising or selling replicas were ‘things’. We’ve seen recently the oil teams using their owners national flag colours for second or third kit choices but other than that, I can’t think that any sponsors etc. have demanded teams choose a certain colour for second and third strips. It’s mostly been determined by the kit makers.