relknes, on 2012-February-27, 21:08, said:
It is also not a relay because opener's response says something about their hand, where a relay bid tells opener something and their response says nothing other than a desire for more information (hence the "tell me more" terminology).
This is untrue. Stayman is absolutely a relay. Most relays say something about the relayer's hand, even if the bidders themselves do not disclose it (or sometimes simply do not understand it). Relay systems have relay breaks. Not using a relay break means that the relay itself has a meaning.
As mgoetze points out Stayman is not on its own a relay system. However it can be part of a relay system with certain follow-ups. Also, Adam has pointed out many times on these forums that what the ACBL means by the term relay system is not the same as what the rest of the bridge world means. A 1♥ response as "hearts or GF" is legal because any given relay sequence leads to game. Of course any given Director might choose to interpret this differently.