shortcircuit - this is a tough one.
Both Ryan (Utah) and myself have spoken extensively with UL about this..the principle engineer at UL for Swimming Pools, tubs, etc. was active in getting this code section revised. He also attends a monthly meeting of inspectors/contractors in San Jose.
The bottom line after much discussion with UL is pretty much this:
If you have a double insulated motor (plastic motor housing with no bonding lug) you DO NOT bond to the water piping or anything else. BTW - these motors are designed such that no part of the circulating water comes into contact with any motor component[thus the language in 2005].
If you have a regular hydromassage tub (i.e. it is not a double insulated motor) then the motor does have a bonding lug on it and it should be bonded....also most any inspector will require it to be bonded if there is a bonding lug on the motor.
Another BTW - only about 1 in 10 of these hydro tubs is double insulated (in our area).
Even though the language has changed there does not seem to be any difference in the installation than pre-2005 (pre-2005 you did not bond to double insulated motors, you did bond regular motors.....it's still the same).
If you want to speak directly with this principle engineer: