📱 Register SIM cards for Staff
It may be alluring to think of a phone number as 'private' and something that doesn't identify its owner if they don't publicly list it. But as soon as someone stores a phone number in their phone book and attaches a name to it - that link between number and name will be uploaded to every service that uses the contacts on that phone to get the names of your contacts (e.g. WhatsApp, Telegram, Signal, Google Contacts, etc). In some cases this number is even uploaded to a publicly available database which acts as a "phone book" for mobile phone numbers.
So unless a number is not shared with anyone, the number and name will be stored together. The longer the number is used, the more likely that it will become known - either to the authorities or to the general public - who the number belongs to.
That is why if someone want to avoid being personally identified and tracked via their mobile number, they should use TWO numbers: one for mobile connectivity (this is the prepaid SIM card that connects to the mobile network), and a second phone number to 📱 Safely use Signal. Once the phone number is registered to Signal, it can be used without the SIM card in the phone. So as soon as the public number is signed into Signal, the second number can be used for mobile network connectivity. This SIM card's number is kept secret and shared with nobody. No phone calls or text messages over the traditional network should be made.
This suggestion of course only makes sense if one is able to obtain a SIM card anonymously as described below. For details on how to set this up, refer to this guide by The Intercept
SIM cards come with identifiers which don't only show that the device is being used in phone calls or text messages, but also where the device is (whenever it has a connection to the mobile network). By using their antenna network, telcos can fairly accurately track and record the phone's physical location. If any of your colleagues have phones on them when they move outside with the mobile connection on, their location would be tracked as well. If you a colleague is then later found out to have been in the same time and place as an illegal gathering, it could pose a serious risk to them.
More directly, if anyone has become a target for enforcement agencies, and they are trying to remain hidden, their phones could give away their hiding location.
What you should do
Different rules and regulations apply to the purchase and sale if SIM cards, so some of these suggestions may not be available to you. If so, simply move on to the next best option for your organisation.
1. Get anonymous, prepaid cards
Ideally, you would purchase pre-paid cards for all the staff in your organisation which is at risk, and would be able to do so anonymously - i.e. you would not need to show any kind of identification so that there is no direct link between the SIM card and the identity of the user.
2. Get overseas SIM cards with free roaming
If you have no way around getting registered when you purchase a SIM card, you could opt for an overseas card that has "free roaming". This will be considerably more expensive than getting a local SIM card, but could help you get around the need to register your SIM card locally.
3. Get prepaid cards for the organisation
If you are required to provide identification when you get a SIM card, ask for the possibility of registering the SIM cards in bulk and directly with your organisation - this way there is at least another layer of obfuscation so that the SIM card is not directly tied to a specific individual. Of course this is only a very thin layer of protection, but it's still preferred over directly tying the cards to your individual staff members.
If none of the above are available to your organisation, be sure to instruct your staff that their phone number will track and identify them where-ever they go.