In today's bridge column, opener opened 1NT with (s)A94 (h)AQ97 (d)763 (c) AQJ. Responder had s)KT (h)KJT863 (d)K52 (c)86.
At two different tables, both pairs got to 4H, but in different ways. At Table 1, responder bid directly to 4 hearts, played and made it. At Table 2 responder bid 4 diamonds (transfer), and opener bid 4 hearts, and was set by a diamond lead through responder's K52, and the K of clubs "offside" opener's AQJ.
My understanding is that the reason for transfer bids was to protect the opener when the responder had a weak hand. For instance, a responder might bid "garbage Stayman" with (s)xxx (h)xxxx (d)xxxxx (c) x. That is, zero hcp, and a clear desire to play in anything except clubs (or NT). Likewise, a responder might bid two diamonds (transfer) with "nothing" and an indifferent five card heart suit. Of course, a responder might also bid Stayman or a transfer, with 8-10 points, while needing help to determine the ultimate suit and level of the contract.
But in the above example, the responder had 10 high card points and a six card suit, enough to bid (and play) game on his own. Why use a transfer in such a case?
Do some pairs play that only two level bids are transfers and higher bids are "natural?" Or do most transfer bidders keep the transfer mechanism even at the four (game) level? Put another way, does a transfer at the two level follow one convention and a transfer at the four level follow another convention?