The problem, stated plainly
A proposal shoot is not a photoshoot with a question in it. It is a logistics exercise with a photoshoot as its cover, and the thing most likely to go wrong is not the light or the wind. It is that the surprise collapses twenty minutes early, in the car, because something did not add up.
Everything below is about that, and it comes from running these rather than from theory.
The cover story has to be boring
The most reliable cover is the true one with a piece removed: you have booked a photoshoot. That is already a complete, plausible reason to be collected from a hotel at an early hour, to be wearing a dress, and to be on a roof with a photographer.
What gives it away is over-explanation. A booked photoshoot does not need a reason, a story about a friend's recommendation, or an unusual amount of enthusiasm from the person who booked it. The people who get caught out are almost always the ones who built a second layer of fiction on top of a cover that was already working.
Tell us the cover story when you enquire, and we will use the same one. The most common failure we see is two people giving a visitor two different accounts of why the car is early.
Where the photographer stands
A proposal inside a booked session is easier to photograph than a proposal in the open, because the camera is already there and already pointed at you. Nobody has to hide in a hedge.
The practical arrangement is a signal and a lens. You agree a signal beforehand (a phrase, a hand on the back, taking a knee), and the photographer changes nothing visible when it comes. The frames people keep from these are usually the two seconds after the question rather than the question itself, so the aim is a photographer who is already in the right place and does not move.
The one thing that genuinely helps is telling the photographer your plan in detail, in advance, in writing. Not the gesture of it: the actual sequence, including which direction you will be facing and roughly when in the session you intend to do it.
The dress complicates a surprise, and that is manageable
Two specifics are worth planning around. The first is that a five-metre train is not a garment you drop to one knee in casually. The assistant needs to know the moment is coming so the fabric is clear rather than under your shoe.
The second is that the ring has to be somewhere. There is no pocket in a flying dress. In practice it travels with the person proposing, and the handover, if there is one, happens before the dress comes out of the bag rather than on the roof.
What we can arrange, and what depends on someone else
This is the part where honesty is more useful than enthusiasm. The session, the photographer, the assistant, the transport and the dress are ours. The roof is not.
A rooftop with a view of the pyramids belongs to a hotel, and anything beyond a daytime photoshoot on it (an evening, music, flowers, a cake, dinner, a decorated space) is the venue's decision and not ours to promise in advance. If one of those is central to your plan, raise it at the enquiry stage and we will find out rather than assume. What we will not do is confirm something a venue has not confirmed to us, which is the failure mode that ruins the day rather than merely complicating it.