>what about do a redirect with a script? cgi, asp
>do they also notice that?
yep. and even if they don't it's not allowed. as soon as one of youe competitors sees it they'll "tell on you"
I'v done it myself to get a better ranking. as someone once said to me, ask yourself if you're trying to trick or cheat the search engine, if you answer yes, forget it. you run the risk of getting banned from the search engine. best case the page will get banned, worst case your whole site will get banned. the engines are getting smarter every day, if they dont catch it today, they will tomorrow.