Detect The Device Thief

Riddle: Ainsley was having breakfast at her favorite café. She went to the bathroom, leaving her smartphone near her food. When Ainsley returned to her seat, she realized that her device was gone; she also looked just in time to see a man rushing out of the café. When she reached the man, Ainsley asked him to give her her device, but the man said, "I know nothing about your smartphone!". As soon as Ainsley heard these words, she took her device back and called the police. Why?

Answer: How did the man know that Ainsley's device was a smartphone?

Source: https://www.riddles.com/index.php/11438

Ainsley was having breakfast at her favorite café. She went to the bathroom, leaving her smartphone near her food. When Ainsley returned to her seat, she realized that her device was gone; she also looked just in time to see a man rushing out of the café. When she reached the man, Ainsley asked him to give her her device, but the man said, "I know nothing about your smartphone!". As soon as Ainsley heard these words, she took her device back and called the police. Why? — Detect the Device Thief by Gabriella Simonetti v1.

Riddle: Ainsley was having breakfast at her favorite café. She went to the bathroom, leaving her smartphone near her food. When Ainsley returned to her seat, she realized that her device was gone; she also looked just in time to see a man rushing out of the café. When she reached the man, Ainsley asked him to give her her device, but the man said, "I know nothing about your smartphone!". As soon as Ainsley heard these words, she took her device back and called the police. Why? Answer: How did the man know that Ainsley's device was a smartphone? — by Gabriella Simonetti v2.