In his turn North asks about Wests bid "is it natural?" and doubles after positive reply. EW summoned TD after the deal (down three; very bad result for EW, because field mainly preempted at the third level and the only game on NS line is 3NT) and stated that the question virtually confirmed that the double is for penalties. NS says that their doubles at fourth levels are always for penalties, that they would double "whenever they see four [defensive] tricks".
Double for penalties on preempts below 4♠ level is virtually unknown around here.
EW is good and experienced pair, but NS are novices, rarely seen in the club and are probably self-taught. Of course, there is no CC (otherwise, there would be no question).
How would you approach the problem? Do you think the task would be any easier if TD was summoned before the end of the bidding?