Pretty self-explanatory - are you required to inform your opponent of what is in your transports?
I'm wondering if this tactic could be used in order to use cheap distraction transports that don't contain anything in order to allow transports with troops a better chance to get to the front. Or, alternatively. I could put nasty troops in a smaller transport in an attempt to trick my opponent into shooting a bigger transport with weaker occupants.
But these thoughts would be pretty much negated if I HAVE to tell an opponent who is in what. I think that in order to keep things fair, I could write who is in what on a piece of scrap paper, and put that paper in each transport.
Anyways, what are people's thoughts? I don't recall reading anything about this in the rulebook.
Until I read on here I didn't realise this was a rule, I've always used this as a ruse, hiding Rhinos carrying Plague Marines in the midst of Rhinos carrying Khorne Beserkers, for example. I've always let my apponent know what forces I was fielding, but as for which Rhinos/other transports are carrying what, it was often something that, whilst I never really necessarily kept secret, I kept under the rug in a sort of "Don't ask don't tell" way.
However, I've rarely been in matches that has involved less the five of my own Rhinos and usually its around eight or nine plus any other transports such as Razorbacks, Land Raiders, Stormravens, etc. I can often maintain that sort of ruse, though, which is less handy for my Blood Angels but more so for my Eldar and Chaos forces.
Though, now I've found out I have too, I guess I'll have to adapt to that.