I think Google actually stand to lose less than a smaller corporation. The registry will not assign Google to another company in any way that passes any eyeballs without seriously questioning it; if it did get re-assigned then they wouldn't have a problem recovering it. It's not likely to be gone for more than a few seconds before it's noticed and customers who were phished, or whatever, wouldn't be that likely to leave Google because of it.
That said I think appeal to authority is quite useful in this situation.
I would agree that any attempt to reassign google.com ought to raise someone's eyebrows.
But I would have said the same about mit.edu and they got reassigned about a year ago. Obviously not for long, but the damage someone well-prepared could do by owning google.com for just 30 minutes is scary.
There's no way anyone could own it for more than a couple of minutes before Google had contacted the managers of the root name servers and ICANN to revert. Like the sibling comment intimates handling the traffic would be nigh impossible - easier to control and perform a localised attack on a nameserver to "own" google.com for a limited subset of users.
The "well prepared" part makes me wonder. What kind of infrastructure would you need to handle google.com's traffic? I don't think any of the cloud providers can scale up to that kind of traffic out of the box, and it's not like someone can just build and staff a dozen data centers in preparation of this hijack attempt.
That said I think appeal to authority is quite useful in this situation.