Scoring: MP
1♣-(1NT)-Pass-(2♦) (*)
DBL-(Pass)-Pass-(2♥)
Pass-(Pass)-3♦-AP
(*): 2♦ was not alerted and I (Dealer) asked about the 2♦ bid and was told it was to play. I kind of thought it was transfer so I asked LHO if he was sure and he said Yes.
No convention cards.
3♦ did go -1.
What is the normal ruling for this?
Without convention cards you assume that the explanation was wrong (?) and with the correct explanation South would have passed, West also passes (because he only knows the wrong explanation) and North passes and they play 2♦?