You haven't been on a bike in years. Trailer, no brainer. There are lots of ways to fall over on a bike. By a near miracle my 2 falls on the road (real dirt biking is a whole different issue) were the extremes.
One was hit from behind. My rear wheel and a skinned knee were the only damage.
The other was from entering a gas station at an angle. That little 1" lip is enough to knock a bike out from under you as easily as if someone tried to kick the bike out from under you.
But I've had lots of close calls, going through running water only to find it had been running for a long time and algae on cement is slick.
Thing is that a kid in a seat both makes the bike unbalanced and the fall when a bike goes down can cause impact like trauma even if the kid never hits anything. (The balance thing is likely part of why another rider suggested staying away from a racing bike).