Not so much because I believe there's much chance of foreign jets or missiles whistling past while we're in the vicinity but rather in case any observers even think they see a camera aiming in the plant's direction.
A few years ago, a tour group member, determined to get a photo of the plant (despite warnings to not wave as much as a hankie in front of the bus window just to be on the safe side), decided to take a snap with his camera on his lap.
He confessed this to me later, adding that he'd got his come-uppance - a nicely in-focus shot of a fellow passenger's hairy stomach poking across the aisle.
All this highly sensitive activity and military presence on the plains is in stark contrast to the drive into Abyaneh.
In early autumn after months of no rain the hillsides were tawny gold and barren. But the valley floor was still a sinuous ribbon of patchwork greens - walnuts, oaks, apricots, apples and pears.
Hobbit-size wooden doors set under triangular portals are set into the hills - places of refuge for shepherds and their sheep during the harsh winters.
Pleasantly cool in summer, Abyaneh's temperatures plunge in winter sometimes to -20 and below.
The village itself is constructed almost entirely of adobe made from the local red clay - visit during a rainstorm as I did once, and the narrow alleys seem to be flowing with blood.
The houses tumble down the hillside, the front terrace of one forming the roof of the property below. Wooden balconies overlook the valley and at most front doors seats have been built into the walls for passers-by to rest on.
Abyaneh is one of Iran's oldest villages and is listed with Unesco. Until the Saffvid era (between the 16th and early 18th centuries) long after most of the rest of Persia had converted to Islam, Abyaneh's inhabitants had remained resolutely Zoroastrian. They followed the beliefs of Persia's most ancient religion which is still practised by a minority of Iranians (especially in Yazd).
Today the village is Muslim but the past lingers on - the men wear baggy black trousers and the women mid-calf length skirts and long white rose-printed headdresses.
Sadly there is little to hold Abyaneh's young people - it's the old who sit outside their houses selling dried fruit and handcrafted jewellery.
Near the base of the village is a tiny but beautiful shrine. A rectangular pool fills the courtyard, which is shaded by an ancient grapevine. A wooden balcony frames views of the tree-filled valley.
The rooftops of the surrounding houses are crammed with shallow woven willow trays covered with the season's fruit crop left out to dry in the last of the autumn sun.
Around the walls of the courtyard are photos of Iran's martyrs - soldiers killed in the Iran-Iraq war.
Seeing their bearded serious faces and remembering the military hardware on the planes nearby it seemed appropriate to take one's shoes off, pad into the shrine and pray for peace.
