Hey, I've had one or two tragic accidents with cars rolling off tables and going "splat" a fair distance below (funny, they don't explode in a fireball like they do on tv.....)
If you want to play with the model, let the wheels roll.
If you want to build to view and enjoy and display, glue the wheels.
Easy. There's nothing wrong with deviating from the instructions........but always dry fit stuff first and think ahead for what else is to go onto the assembly.
Cheers,
LeeTree