Cancellation fees

Hi Friends

We have been noticing for many years that whenever we marked a guest as "NO SHOW", there is an instant cancellation message of that particular booking from 'www.booking.com'. We believe those messages are not sent by the guest, in fact, can not be sent by the guests so quickly. It seems something like an automated procedure by 'www.booking.com'. Pl. give me more clarity on this issue. Thanks