Your knowledge, as well as MANY other hams, is incorrect.
The FCC is abundantly clear that the amateur radio licenses provides precisely ZERO authorization to transmit outside the very clearly defined amateur radio bands.
Transmitting outside the ham bands, even in an emergency, real or imagined, is against several FCC rules. There is not secret hidden rule. There is no misunderstanding. There is no waiver.
Here it is again:
97.405 Station in distress.
(a) No provision of these rules prevents the use by an amateur station in distress of any means at its disposal to attract attention, make known its condition and location, and obtain assistance.
(b) No provision of these rules prevents the use by a station, in the exceptional circumstances described in
paragraph (a)of this section, of any means of radiocommunications at its disposal to assist a station in distress.
Key words are "these rules". These rules are Part 97. Part 97 -only- gives authorization to use Part 97 frequencies. Part 90 frequencies are NOT the same as Part 97 frequencies.
Transmitting under any other radio service requires following the rules of that radio service. Specifically, licensing, type acceptance, etc.
FCC Part 2, known as the "general rules" that apply to all radio services, including amateur radio says:
§ 2.405 Operation during emergency.
The licensee of any station (except amateur, standard broadcast, FM broadcast, noncommercial educational FM broadcast, or television broadcast) may, during a period of emergency in which normal communication facilities are disrupted as a result of hurricane, flood, earthquake, or similar disaster, utilize such station for emergency communication service in communicating in a manner other than that specified in the instrument of authorization: Provided:
(a) That as soon as possible after the beginning of such emergency use, notice be sent to the Public Safety and Homeland Security Bureau of the Commission at Washington, D.C., stating the nature of the emergency and the use to which the station is being put, and
(b) That the emergency use of the station shall be discontinued as soon as substantially normal communication facilities are again available, and
(c) That the Public Safety and Homeland Security Bureau of the Commission at Washington, D.C., shall be notified immediately when such special use of the station is terminated: Provided further,
(d) That in no event shall any station engage in emergency transmission on frequencies other than, or with power in excess of, that specified in the instrument of authorization or as otherwise expressly provided by the Commission, or by law: And provided further,
(e) That any such emergency communication undertaken under this section shall terminate upon order of the Commission.
Please notice that it says "except amateur", meaning that amateur radio does NOT have permission to do this. No fine print, no waiver, nothing.