The retractable leashes are some of the most dangerous consumer items one can purchase. Before you extoll the virtues of your ignorant self absorbed use of these leashes, google them. You will find countless incidents where serious injuries were incurred... Fingers severed, bones broken after getting tangled up in the 30' of line etc. The simple truth is you can NOT control your dog from 30' away... and you know it!
The bottom line is that most CG's require a 6' maximum leash and no one is exempt from that rule! There are lots of very good reasons for the 6' requirement, hence the frequency with which you will encounter it. If you will not comply with the rules of the CG please go elsewhere.
:S