Professor X has invented a new, nearly unstoppable robot as an "ultimate test" for the X-Men:
"Excellent, Jean! You brought the blanket to us in record time!" Which implies that she regularly snatched blankets from Xavier's lap, and Cyclops timed her.
If you consult older editions of the Guinness Book Of World Records, you will see that Jean Grey did indeed hold the unchallenged record for "Fastest Blanket Bringing" for many years.
From X-Men #22 (1966)