Lost device contact.

[userb3jRz03R2P]

I added my telephone number to my Samsung Galaxy A36 lock screen, imagine the ability of someone finding your lost device having limited access using the device to send a message such as their phone number or where to pick up the phone. Imagine someone finding a lost device and taking it to the customer service center saying I found this device in the parking lot or left in the shopping cart, then the service center will notice an email or telephone number on the lock screen in which there would be able to use it in a limited capacity to send a message, they could call the number and the message would automatically going to voicemail or to the email link to the telephone number or text a different telephone number, they could say we have your device and you could find it at such and such customer service center. 

[Pianodude58]

Adding contact info to your lock screen helps honest finders return a lost phone but creates big security risks, making you vulnerable to phishing attacks, identity theft, or scammers who could use your visible details (email/number) to try and unlock your device, guess passwords, or access linked accounts, especially if it reveals personal data.

[userb3jRz03R2P]

I am receiving a scam calls from India on weekly basis, unfortunately personal information is no longer private, anyone with a computer and some information as how to do it can get any information on anyone, I contacted Earthling to reset my email password and they sent me to India, after they got my phone number I had nothing but trouble, Indian scam artist from right left and center we're calling me,
from one scam after another after all a telephone number is what they need, my only other option is to cancel my phone number and get a different one, even with replacing your phone number is not a guarantee that they will not be able to track it.

[nullandvoid]

You could get a free Google voice number and give that out or call from that number when you have to call unknown or sketchy entities - or customer service/tech support.  Google voice has better spam protection than the native phone dialer and it protects your own phone number. You can even forward all your normal phone traffic to that number.  By all means, keep your own phone number on your display if you want to invite even more spam calls.

[nullandvoid]

While adding contact info to the lock screen makes it convenient for a finder - likely using an email address is better.  What good is adding the phone number of the phone you lost?  How are you going to get the call?  Anyway, a finder of a phone can always access and call emergency contacts, as someone did when my sister lost her phone.  Emergency contacts are easy enough to access from the lock screen without having to unlock the phone, and the ability to call *only* those numbers (and 911) is built in.

[Robin621k]

My message is, Robin's phone call, brothers number if found.

[nullandvoid]

I use my name and my own (junk) email address.

[userb3jRz03R2P]

As they call me and I do not answer it will go into voicemail, then I'll be able to get it through my computer at home or any other device.
some voicemail services such as Google Voice will send an email message with the voicemail content.

[Robin621k]

I never answer the phone if they are not in my contacts, if it is important they will leave a voicemail. My outgoing message clearly states this.

[nullandvoid]

Yes, but someone who found your phone may not leave a message, as they figure if they have your phone, they have your means of receiving voicemail.