If so, that's a tough problem. Distrusting your 'users' (content providers) and double-checking them is likely to generate a fair bit of hostility, especially for a non-opt-in service.
To be fair to Google, they do get inundated with spammers, so a certain level of distrust is understandable. The problem is that like Pierre mentioned this is very easily gotten around, which makes it fairly ineffective, and to anyone who actually uses traffic logs for any kind of stats tracking, any fake referrers can be quite annoying.
If they don't generate too much extra traffic, then I don't see any problem with spot-checking people. If it's a small amount of hits, then the faked referrer should just appear as noise.
Now, if it's a lot of traffic, then you might have a problem, but the post showed something like 2 hits. 2 hits from a crawler does not a spammer make.
