I wouldn't say that actually... its not something you need to go chasing around or monitoring, because if you set the keywords low, ie. DI has it default at 10 I believe, and 30 day expiry... so only the most relevant top 10 keywords should show for any page, and those should be what the page is being found for the most.
If you stumble onto it, ie. looking in your stats or viewing the page as an admin, you see some completely irrelevant term listed that you don't want associated with your page, could even be a porn term or such, then you could copy it, search it in the ACP, remove it instantly which bans it from being used again.
I haven't looked at mine since installing... I only review things every few months... I look at them when viewing pages, quick browser over, etc. If you keep the ACP settings minimal, then you really don't have to worry. But every now and then, some stupid thing like a single letter or such, will become a prominent term, which isn't what you want, or suddenly you see some keyword phrase in your stats climbing up the numbers, so you investigate because it looks odd.
Leave it minimal, its near set and forget. Expand it outwards... you do need to be a bit more pro-active with what you're doing so you don't get yourself banned.