In the typical Dobsonian, it is far more likely that the rocker box and or groundboard will flex the few millimeters, than actually rock. However the amount of flex will vary as you push on the scope, giving a springy kind of rocking.
> 15psi/sq inch
Redundant redundant? Duh. I meant to type "15 pounds/sq inch" (is a metric guy going to know what a psi is?) but my hands went ahead and tried to abbreviate it while by brain was not looking...
Chuck