Uh, no. Especially not if it's the way you describe it. If you can stay there till you decide to leave, the seal clubber will simply make money to get the best ship available in there and then go seal clubbing. It's not like he'll have to be afraid of experienced players coming in and giving him trouble, either.The way I'm reading it, the new pilot can stay there indefinitely, but is allowed to leave any time after they make their first rank....yay for the end of seal clubbing!
If people get forced to vacate once they get their first rank upgrade, things will be a bit better. Seal clubbers will have to specialize in Sidewinder setups with costs below the first trade rank upgrade. That'd still be a noticeable advantage over people in e-grades Sidewinders, but seal clubbing then might require a minimum level of skill, which will block most of them from being successful.