The BC Agricultural Land Commission came into effect in 1973 to protect valuable farm land from development. It has extensive rules on the use of land designated for farm purposes and has as it's mandate to protect agricultural property from being used for other purposes. Trying to rezone or get land out of the Land Reserve or ALR is difficult if not impossible. So if you are buying land with the intention of being able to do something outside the regulations you will be in for a fight with the Land Commission. You will occasionally see land that operates outside the regulations but for the most part this land use has predated the legislation and its use is grandfathered.
Some ALR land can accomodate more than one residence by zoning or regulation but this is with the approval of the ALC and it is not easily obtained. To give you an example a friend had 18 acres in the ALR and wanted his parents to be able to build on the land with him. The closest he was allowed was a one year tempory permit for a single wide trailer, not a double, and it could be renewed yearly. Once the parents moved off the land the mobile home had to be removed.
On way to justify a second residence is for farm help howver this is not a get out of jail free card. You must be able to justfy the workload on the farm to be greater than what the primary resident is capable of doing. As an example the numbers flotaed around are that the work load must be 150% great than what one person can do. If approved the second residence is limited in size to approx 1000 sq ft.
Over the last 40 years most residents of BC have become use to the ALR and its regulations and most local governments and residents support the purpose and mandate.