MyDefrag uses the Windows "layout.ini" file, which is a record of all files accessed while booting. The list is only updated in certain circumstances, for more information see the MyDefrag ImportListFromBootOptimize
manual page. So, if for example you have not booted in a month then yes, the file may list files that have not been accessed in a month. This does not mean the list is incorrect, and does not mean the files should not be placed in the boot zone.
I had of course in mind regular booting.
I have noticed in past, that on Vista, at some circumstances,
there are listed files with last access several months ago.
It is related to VirtualStore feature, when file request is redirected
from Pragram files folders to User VirtualStore folder.