Madchemist tried to do that last game and Marshall told him he could not. At least I'm pretty that's what happened.
Yes, that was indeed the case then.
Okay, well, I'm sorry that happened and if I'd been watching more closely as I spectated I probably would have said something. However, I have to say that you definitely can move into a minefield. Moving over a revealed non-unit does not constitute an attack. Supply caches, industrial centers, roads, and minefields are all non-units and you can move over them AND capture them without attacking them.
While I'm not sure that this has ever come up for a minefield before, I've said this many times.
I think the point of confusion is that if the non-unit is NOT revealed, ie: if it is an unknown on the map, then it must be attacked. However, if it is revealed, you're more than welcome to roll right over it.
For absolute clarity, where it says in the rules:
A unit that strikes an enemy minefield (attacks or attempts to move through) [...]
This means either attacking or attempting to move through the minefield. You do not have to attack a revealed minefield. You can move onto its hex without attacking.
EDIT: Of course, you can ALSO capture a supply cache or an IC by attacking it instead of moving onto it. It is difficult to envision a circumstance where you'd want to do the same for a minefield or a road, so I'll defer judgment as to whether that is possible.