Loopholes. It seems that your are unfamiliar with this term in a FF and Flying context.
Incorrect but thanks for playing
The context I'm referring to is a direct contradiction of T&Cs without an apparent basis. By definition, a loophole has a basis ... otherwise it'd just be a hole
Typically, the basis is an ambiguity (such as a contradiction between T&Cs), an omission, a failure to address certain circumstances or new circumstances that have arisen since the T&Cs were originally created. In the case of gift vouchers, it's the inability of electronic systems to enforce the T&Cs.
In this case, it would appear to be something offered by phone agents in direction contradiction of the T&Cs but with no technicalities, interweb hacking or Jedi mind tricks involved. (Of course if there is a basis, that would be interesting and useful to know.)
This is an issue for a business as it either means they're willing to do something that they explicitly state they do not (meaning foregone revenue opportunities plus potential customer discontent), or otherwise (and more concerning), that call centre staff are knowingly breaching T&Cs that the business wishes to be upheld.
Inherently, phone agents (especially outsourced ones) should refer to T&Cs. The previous time I called to enquire about gift vouchers, the agent did read through the T&Cs - and since at that time the $2 clause was omitted from gift vouchers, I got my $1 residual value voucher through that loophole
Anyhow, today I called to casually enquire and was told (by the premium line) that gift vouchers can be combined - but the phone service fee would apply. Of course there's always HUACA.