Allow me to quote the relevant section of the Charities Act 2011 which applies
30 Charities required to be registered: general
(1) Every charity must be registered in the register unless subsection (2) applies to it.
(2) The following are not required to be registered —
(a) an exempt charity (see section 22 and Schedule 3),
(b) a charity which for the time being —
(i) is permanently or temporarily excepted by order of the Commission, and
(ii) complies with any conditions of the exception, and whose gross income does not exceed £100,000,
© a charity which for the time being —
(i) is, or is of a description, permanently or temporarily excepted by regulations made by the Minister, and
(ii) complies with any conditions of the exception, and whose gross income does not exceed £100,000, and
(d) a charity whose gross income does not exceed £5,000.
(3) A charity within —
(a) subsection (2)(b) or ©, or
(b) subsection (2)(d), must, if it so requests, be registered in the register.
(4) In this section any reference to a charity’s gross income is to be read, in relation to a particular time—
(a) as a reference to the charity’s gross income in its financial year immediately preceding that time, or
(b) if the Commission so determines, as a reference to the amount which the Commission estimates to be the likely amount of the charity’s gross income in such financial year of the charity as is specified in the determination.
So these are the conditions for not requiring to register and I have highlighted 2(b) as this refers to the current position for RAFAC in England and Wales. HOWEVER I recall in 2009 it was stated by the Charity Commission that the ‘Excepted’ status was no longer going to be allowed to be used in new situations. Further, every CivCom in Northern Ireland and Scotland are registered because under their regulators, you are a charity or not. So the RAFAC sits uncomfortably across two positions. In England and Wales, there have been lots of noises that the Charity Commission will follow suit - hence the suspension of any new ‘Excepted’ charities.
The practical knock on of this at squadron level is that to retain control, ATC-HQ must effectively re-use Exception Orders (identified by the exception number each squadron is given and asked to quote) to avoid Civcomms having to register and thereby becoming non-dependent on RAFAC (although they are acknowledged to be fully independent charities. ATC-HQ will undoubtedly regard that as a loss of control and so would rather merge poorer squadrons under an existing Exception Order than face the creation of numerous new independent charities which they cannot give the impression they have control over, having already lost Scotland and NI (and further islands).
I think if you re-read the Scout text, you will see it does correlate to the extract I have given, but that property is not included in the criteria. (BTW not all land is owned by RFCA and their buildings are on alternative land or even in schools through CCFs). That said, lets not forget that squadrons with minibuses and lots of squadron kit all have sizeable charity assets for the squadron to use.
Also, clause 3(b) is important as it means any CivComm wishing to register can do so without obstruction and this may be beneficial in many cases, if only to remove the smoke and mirrors.
Echoing other posts, the ATC itself is not a charity and is also not a legal entity, so it really is relying on perpetuating the smoke to avoid having to deal properly with it.