Why should we trust what they say about their spending?

You know how there is a general truism that you shouldn't trust statistics, and especially not if they come from the Government? Well.. some may say that sort of view is terrible cynical and helps solidify the anti-politics attitude that is pervasive today. However, sometimes they really don't do themselves any favour.

Take for example this document on the Cabinet Office website which apparently overseas visits made by all Ministers costing in excess of £500. Why does it not contain the £4,584 first class trip to New York that Barbera Follett took during the same period whilst a minister at the Government Equalities office?

Probably an oversight because the department in question exists only to placate Harriet Harman when she didn't get the Deputy Prime Minister title so was likely forgotten about, but still, if you're going to say you're listing "all Ministers" travel and then forget about 4.5K of spending, what faith can we put in the list as whole?