First of all look after the BIT, it has been after a jump, and some players are not aware of the rules of the stop card, so look ask further questions.
Second, there is MI, so the contract of the table should be 4
♠.
Third, there is a possible use of UI, it has no importance on the final result, but you might provide EW a PP for using UI, I agree with Mark that double is clearly suggested by UI, but 3
♠ its not enterilly clear, I think pass is a LA but some poll would be needed.
I think that for a PP it would not be enough for pass to be a LA, it would have to be a clear LA making 3
♠ a blatant use of UI but I am not completely sure.
Another question, if I have to make the poll among players who have already played the board and will be biased as we all know for knowing the full hand, In my opinion I would get more realiable results if I made a litle trick and asked them this question:
Is it allowed by the rules?
Australia, matchpoints, daytime club game. NS better than EW.
North did not alert 3♦, though preemptive jump raises are alertable in Oz.
Limit raises are "standard" in this club.
Director called when East bid 3♠. EW acknowledged.
Ruling please & would it change in other circumstances.