At the beginning of the film The Martian, part of the dialogue implies that one of the crew has the job of monitoring the MAV to check it is still upright. The importance of this job is clearly shown when a storm hits.
Later we find out about another MAV which will be in place for a significant period of time before it is needed, yet no one shows any concern that it may also be at risk of toppling.
So given the importance of this escape craft, why wasn't any plan in place to tether the first craft? And were NASA just gambling on the weather that the latter MAV didn't topple before it was needed?