If the 1
opening is Precision then 1
is alertable, so East alerts it and assumes it is Suction. He is not allowed to take any notice of whether his partner has asked any questions. Anyway, his partner may know whether it is or not from what the opponents said at the start of the round or from the convention card.
If the 1
opening is not Precision then 1
is not alertable, naturally.
If East does not know what the 1
is then he alerts. If asked he says "If the 1
opening is Precision, then 1
is Suction, showing .... If the 1
opening is just a short club then 1
is natural."