It seems that even non-pilots have no problems understanding what a "solo" flight actually means. For those who may want to quibble the FAA regulations (for those flying American registered aircraft, which the Stearman is) seem pretty clear;
14 CFR § 61.51 - Pilot logbooks;
(d) Logging of solo flight time. Except for a student pilot performing the duties of pilot in command of an airship requiring more than one pilot flight crewmember, a pilot may log as solo flight time only that flight time when the pilot is the sole occupant of the aircraft.
On the matter of TCT's previous clarifying statements, by her own account these appeared on 11th June 16, 13th October 16 and 24th October 16, quite a long time after awards had been announced/collected, and a well after the matter first came to light.
The door has now been clarified as being shut by TCT, but it took until the horse had bolted for her to do it.