Earlier quoted context omitted.
> Also lack of local sim doesn't mean you aren't transmitting. Yes and no. Airplane mode, turning your phone off, etc. But also, even if your phone is pinging the tower with your device’s IMEI... how would they know it’s your phone’s IMEI? There’s no registry mapping IMEIs to legal identities, in any country, AFAIK. Carriers have that information, but you wouldn’t have yet signed up with any Taiwanese carrier. So the…
This is probably thinking too high tech for some basic human int collection. It's easy enough to collect imei numbers at a checkpoint. It's also easy enough to find out from family members and friends and business connections (everyone works for someone, has a family, and friends, and even if none, there's always a bank account that paid for the airline ticket somewhere, attached to a passport). Think low tech. Taiwa…
True enough, I guess. Require that you turn all devices on, then either require unlock and look at the IMEIs yourself, or pass the person through a Stingray in an RFID cage.
But I would assume that if Taiwan was doing that, people would notice (requiring turning devices on is a very unusual step) and would have mentioned online somewhere that that’s something that happens when you visit Taiwan.
Also, it still won’t help if this immigration-evader turned super-spy is rolling their spoofed IMEI regularly.
(Also, where would they get the information on who your boss/company is? From your customs form? That’s one of those things too expensive to verify for every case ahead of time, so they won’t bother until they actually want to find you; in other words, that’s one of those things that’s perfectly easy to lie about. From your visa, presuming you need one? Information like that could be entirely outdated by the time you visit.)