You can get an idea about how sloppy the joint is with a simple model. If you look at the tubes as rigid bodies then this schematic shows how much one end of the pole will move if you clamp down the other.
The inner sleeve can tilt up an angle 2*(0.009)/6 = 0.003 radians, and the right pole section can tilt up an equal amount. So the total tilt is 2*0.003 = 0.006 radians. At the end of a 72" long pole section, this is a distance of 72*0.006 = 0.4" slop.
This sounded like a lot, so I decided to do some things to reduce it.
First, I decided to bond the inner sleeve into one end of the pole. This cuts the slop by two.