Is a 301 redirect also a method for hijacking or PR loss?

[catch2948]

I recently discovered that someone had several google listings, which appeared during an "allinurl:www.mydomain.com" search. All of these listings had urls structured as follows:

www.otherdomain.com/go.php?url=<random code>

but when clicked, all of them go to www.mydomain.com ... Originally, I thought that this was a 302 hijacking, so I ran HTTP header tests, and in all cases, the top 2 lines of the read out were:

HTTP Response Headers
HTTP/1.1 301 Moved Permanently

Is this another form of page or PR hijacking? A lot has been mentioned here concerning 302 redirects, but I couldn't find any threads concerning the external use of a 301 redirect to another site, by another webmaster.

Thanks in advance for your replies.