Well, they are wrong.
The leading jump trainer has now decided to run his exciting prospect in the Supreme Novices' Hurdle, the opening race of the Festival meeting.
Henderson said: "He's very good and he goes for the Supreme.
"I have been speaking to AP (Tony McCoy), Frank Berry (racing manager) and JP McManus (owner) and that is now the plan."
Henderson wants to put a number of his big Cheltenham hopes through their paces in a workout after racing at Kempton on Saturday.
He said: "Barney Clifford (Kempton clerk of the course) has allowed us to work some horses after racing at Kempton on Saturday.
"Long Run, Binocular, Bobs Worth, Kid Cassidy and Rolling Star are going as part of their preparations."
Henderson added Riverside Theatre would join the travelling party at the Sunbury circuit.
Finian's Rainbow floundered in soft ground at Ascot at the weekend, and is now poised to defend his crown in the Queen Mother Champion Chase.
The trainer said: "Barry (Geraghty, the jockey) is adamant he doesn't go on soft, and I think we're looking at two miles (Champion Chase)."
Elsewhere, BBC Radio 5 Live have signalled their continued commitment to racing by announcing they are to broadcast all 27 races at the Festival.
Jump racing's premier Festival will be the first big meeting the station will cover having agreed a new four-year contract with the Racecourse Media Group.
Joining 5 Live's team are former Channel 4 presenter Derek Thompson and veteran jockey Andrew Thornton.