Giving fake phone numbers

I am considering changing gyms. However, their marketing policy involves trading contact numbers for a registration discount. For instance, by providing 15 contact numbers, I can receive a 50% discount, reducing my fee from 40 euros to 20 euros. However, I find it unethical to share others’ contact information in this manner. Unwanted calls qualify as spam, and no one appreciates being on the receiving end of them. I still want the discount though.

What follows is my way of solving this conundrum.

I created a Python script to generate 15 random mobile numbers, from Portuguese phone providers.

# Function to generate (pseudo) random portuguese numbers
def fake_numbers(n):
    prefixes = ["91", "92", "93", "96"]  # Portuguese prefixes
    numbers = []

    for _ in range(n):
        prefix = random.choice(prefixes)
        print(prefix)
        random_number = "".join(random.choice("0123456789") for _ in range(7))
        final_number = f"+351 {prefix}{random_number[:1]} {random_number[1:4]} {random_number[4:7]}"
        numbers.append(final_number)

    return numbers

random_numbers = fake_numbers(15)
print(random_numbers)

The output of this script is of the form:

['+351 911 111 111', '+351 933 333 333', ...]

These numbers are hopefully non-existent. Instead of repeating digits like 1s and 3s, the script generates a sequence of 15 random numbers.

However, all this does is the creation of what are hopefully fake phone numbers — with “hopefully” being the key word. Once the numbers are generated, I need to verify whether they are in use. I do not want to distribute someone’s phone numbers, even if I don’t know the person.

A straightforward method to verify the usage of a phone number is to call it. However, doing so would leave a trace of my call on the recipient’s phone, revealing my number, which I want to avoid. To minimize this risk, I use two strategies:

• Checking if the number is registered on WhatsApp;
• Checking if the number is registered on MBWay¹;

If the number is registered with either service, I alter it by changing one digit and then re-check if this new number is still registered. This process is done manually.

Once I identify a number that isn’t registered on either WhatsApp or MBWay, I proceed with the final verification step: calling the phone number. Out of 15 numbers that were not registered on either platform, only one was active. I repeated all the steps, and ultimately, I ended up with 15 unused, presumably fake numbers. Now, I just add fake names and there we go.