I've seen some high GOO totals, but this is ridiculous...

You know, rather than complain about something that has nothing to do with you -- if it really bothers you that much, just defriend the person -- you should be glad that somebody had nothing better to do with their life than to personally boost the community total by 100,000. But just so you know, you could get 100,000 goo through exploiting glitches, it does not automatically require a hack (though I do agree, it's most likely a hack of some kind).