There's been no direct evidence of a dust devil going over Spirit.

It's a common missconception that the DD's are responsible for the cleaning of Spirit - this is untrue.

Firstly - Opportunity have been cleaned in a similar fashion ( just to a lesser degree ) without there being any evidence of dust devils at Meridiani.

Secondly - Spirit's largest cleaning events have happened at night - when there can be no DD's.

Spirit may have had a DD go over the top of her, but there's no real evidence for it. There's evidence for just strong winds (infact during a DD imaging sequence, Spirit was seen to rock slightly by being blown about by the prevailing winds)

Doug