Since nothing pathogenic can grow in beer there is nothing that can harm anyone. There may be some awesome beer in those bottles.
To put it in perspective, in the Dec 07 Zymurgy Charlie Papazian reviewed bottles of homebrew going back to the first AHC competition that he had stored, and none of them went bad, some had not held up but most of them he felt were awesome...We're talking over 20 years worth of beers.
This is a great thread about one of our guys tasting 4-5 years of his stored brew.
And I brewed an og 1.150, 150 IBU barleywine that I won't be opening for 5 years.
Not to mention the fact that there are vertical tasting for certain beers like Stone epic, where people collect each years beer and then sample a flight of them going back in time.