you did exactly the right thing.
Fine you may never know.. but the feeling was strong enough for your mother to call you.
As a mother its hard, I know.. my son 17 rides a motor bike.
When he first got his bike, ( he rode a dirt bike when he was younger, and also drives a go cart on the track.. pluss he got road experience on my scooter ) I knew he would have a problem at some stage.. a mothers fear or intuition, who knows.. but when he called from the side of the road a few weeks latter saying he came off I was glad... the bike ( bought out of the show room ) needed work.. but he was walking and had that problem I knew he would have.
last week we were at relatives a couple of hours away. he rode down to show off his bike.. coming home the next day my brother in law and he arranged to have a scenic ride home. My daughter who is a spirit magnet said she had a bad feeling when we got in the car to leave.. dread came over me, I also had a feeling.. but I also seen him standing up but shaken after... The accident never happened..
perhaps seeing him standing after was my intuition saying a mother fears were just that..If the I had seen sirens or him not moving I would have talked my son in letting another brother in law have a ride back to our place.. but would he do that..
Some things are not preventable no matter how much we know... or years I was aware of people with broken legs ... I broke my own leg.. lol. I dont know life is like playing cards.. knowing when to hold them, and when to fold them..something that we just have to learn..
Strongly intuitive doesn't always lead to best choices

).. lol. tho they should, I'm just human..
You did the right thing.. you didn't share your fear with your son. or hurt him any by just playing it on the safe side this time. Just try to determine the difference between a mothers fears and premonition. when you master that come back and tell me how

)
Its so much easier knowing the difference when they are not our own sons.