There have been several recent reports of security guards patrolling the Bill Graham Civic Auditorium near San Francisco. It has been indicated that this is in preparation for an as-yet-unspecified event in early September – could it be the event at which Apple finally unveils the iPhone 6S and 6S Plus?

Local news site Hoodline has pointed out not only the presence of San Francisco Police Department officers and private security guards at the building, but also nearby sidewalks that the public have been barred access to and huge power generators placed in a parking area close by.

One of the security guards would only reveal to Hoodline that the venue was closed until September 13 for a “private event”. That event is, according to documents filed with the local Planning Department, a “trade show” running from September 4 to 10. However, this is, so far, seemingly the only evidence of any trade show or other event scheduled at the building at that time.

Assuming that Apple has covertly booked these dates, they would give the company plenty of time to prepare the venue for unveiling new iPhones and possibly new iPads in a major event likely to fall on September 9. There is no consistent venue for Apple’s annual September event, with many previous iPhone models having been unveiled in different locations in the San Francisco Bay Area.