I know the use of of bolts/screws etc are not banned from being used on the mini bot. And the description it they fall under is very general, so are springs allowed for the mini bot?
Surgical tubing is, and it makes a very good spring.
Surgical tubing springs are allowed as long as they do not contribute to the vertical motion of the robot. This is very important. The actual upwards power MUST come from the motors. That said, you can still use surgical tubing for holding parts together (for example, you might have a latch that you want to spring, that would be fine since it does not provide lift to the robot).
The first team update covers this: The only acceptable form of stored energy (for vertical motion) is the battery pack.
<G19> After DEPLOYMENT, MINIBOTS must remain completely autonomous and move
up the POST solely through electric energy provided after DEPLOYMENT by the
permitted, unaltered battery and converted to mechanical energy by the
permitted unaltered motors (and associated, appropriate circuitry).
Violation: The TOWER on which the MINIBOT is DEPLOYED is disabled. If the
MINIBOT is not deployed DEPLOYED on something other than a TOWER, then
the ALLIANCE’Ss TOWER upon which the highest RACE SCORE was earned
will be discounted
They wouldn’t be used as stored energy for vertical motion, more of use in a door mechanism.