The whole incident has me very concerned as well. In looking thru the photo sequence on Drudge, it looks like that one SS agent is the only one who got in. Many more SS agents were still kept outside arguing with Chile security. One agent isn't enough to adequately protect.
I know nothing about SS security protocol, but it seems to me that at some point they need to open fire to eliminate whatever seperates them from the president.
I would think at least two agents should be glued to his side at all times---photo ops be damned!