A word of advice, Shadow. Try not to insult Yeerks on a forum that is full of them. We have feelings too, you know.
As far as Yeerk Pool entrances are concerned (*veers back on topic*), I'm fairly sure the weight room at my climbing gym is one. I was belaying a friend a few weeks ago and suddenly heard a ton of yelling and screaming coming from that room. Someone was shouting "NO! NO YOU F*****R, YOU CAN'T TAKE ME!" and then abruptly stopped shouting. No one around me paid any attention, but they were all employees.
Freaked me out. I would have investigated, but I was tied to a rope and my friend was dangling 30 feet in the air. I thought it would be prudent to avoid dropping them.
Besides, I have a big enough gashad on my head that using local pools is probably a bad idea...