In the current climate of death threats to MPs, stabbings on the streets, throwing of liquid and the possibility of substances which can maim or kill, I think we have to accept there is high tension and MPs will be on full alert, probably having had advice from the police.
The woman was carrying what we now know were papers, but it will just seem like a large white package in the blurr of the moment. There was also a handbag.
She appears to have got closest to the top table with nobody pursuing her and - if she had sprayed acid or even splashed a milkshake - everybody would be saying: "Why didn't somebody stop her?"
In the confusion and noise at the bottom of the room it is quite possible people at that end didn't hear them "announce who they were" but what they will have realised is that there was nobody in security nearby and she was carrying something. In a room full of MPs and industry chiefs.
She was, indeed, grinning, during the tough removal.
I think he was hustling her away from the guests as quickly as he could, while trying to ensure she couldn't do anything with the two objects she held.
If my son or daughter had been sitting at that table, I'd have been glad somebody removed the unknown level of "threat" first and asked the question later.