Balmoral: The Right to Roam and the Royal Family

The Queen maintains a large estate in Scotland called Balmoral; originally built during the reign of Victoria, it has been the favourite get-away spot for all British monarchs since.

Legislation opened up several paths through the estate, such as Ballochbuie Forest, and the roamer has the opportunity of either professionally guided or self-guided walking tours. Some of the paths are patrolled by royal security guards.

The literature, however, advises against roaming when the Royal Family is in residence. This generally includes the common law holidays like Christmas and Easter, but the months of August and September are also given as likely times when members of the Royal Family are there.

How to know when the Royal Family is in residence? Surely there's a way to know beforehand; the alternative is to drive all the way into the highlands and start the roam only to be encountered by the security guards and this isn't reasonable.

I have checked HM's schedule and the only thing listed for Scotland is a perfunctory event in Aberdeen.

Question: how to determine if it's ok to roam on the Balmoral estate? Specifically, when the Royal Family is in residence? and secondarily, what happens if you are encountered by royal security guards if you are roaming during a period when roaming is not advised?

Clarification: Royal Family in this context refers to any living person with a direct blood line to George VI. The Duke of Gloucester, for example, doesn't count.

Clarification: "beforehand" in this context means knowing for certain at least 7 days prior to starting the walk-about so as to enable a reasonable planning time.