I have started to wonder about the apparently poor headquarters security of the Austrian army. The barging in by Berthier and his entourage prior to Wagram and after Marengo is fairly obvious. Add in the stealing of the plans for Rivoli and the access by spies with bungs for information at Ulm and at various stages of 1796, something that evidence is also pointing to at Austerlitz, and it looks bad. Then there is Varnhagen Von Ense riding around in his blue Prussian uniform prior to Wagram and remarking on the fact that he went unchallenged. But I think I have now found the worst example from Theresienstadt (a fortress now in NW Czech Republic) in 1794 https://books.google.com/books/about/Journal_général_de_la_guerre.html?id=e41SAAAAcAAJ
On p.1232 is the story of a French spy, who presented himself at this important fortress with fake authorisation and dressed as an Arab prince from the area that is now Lebanon. The fortress commander gave him permission to look round in the company of an engineer officer. It was only because a sentry, who had served in the French army, recognised him as his former captain that the spy was caught. 🤦♂️ He was arrested at dinner the next day and several important documents and plans were found on him.