The reason we have res slots though, IS to kick people. No, it's not as harsh and cruel as it sounds. The reasoning is thus: We want to have good people on the server. We're prepared to deal with some people having to get kicked off in order to make room for people that we know we like to play with. Even if its annoying for the people that are kicked, we'd still rather have someone we like playing with to be able to get in all the time, over having 'nice' reserved slots that won't kick anyone to make room for an RS player. A slot means something here, it means you were selected by the community as a good player and good all around person and we like you enough to want you around all the time. It's not like servers where only the admin's friends get slots. Or servers where you can buy your res slot. Here, it's a token that says 'we like you over every other random player out there, feel welcome back any time, we'll clear out a seat for you if we have to.'
Often an annoying player who has yet to break the rules has been kicked so that an RS player can join up. Saves the admins having to watch this person who may eventually break a rule, but who has done nothing wrong yet, just acted generally not nice. Yes, sometimes a nice player gets kicked as well, but if we like them and they like us, they'll usually come back and get noticed and eventually get slotted.
So there is a method to the madness. We do want slots to kick people off and make room for people we already know and like. That's why having limited numbers of RS slots is a bad idea. Besides, it's not uncommon lately to see the server filled to the brim with reserves. Having a scant 3 or 4 hidden reserved slots wouldn't do anything when 15 slot holders want to play all at once.