It's a tough call to make.
BCAA does some kind of 100-point inspection. However, some of those 'points' include stuff like 'make sure seatbelt is functional' or 'lights turn on'. They definitely cover a lot of details, but the question is 'to what extent'? For example, they might look for rust on the panels, but they won't look for scratches and small dents. They might make sure the power windows work, but they won't mention whether the motor is weak, or whether the windows squeek like crazy. What the checklist doesn't detail is the condition of the engine or the transmission, or the drivetrain ... all of the larger components.
Think also of a dealer: these are professionals who are trained to sell used cars. Do you not think that they also have the checklist that BCAA uses? I know that if I were a dealer, the first thing that I would do is make sure that my used cars conformed to that checklist. Knowing that BCAA doesn't look at certain things, I might also be inclined to overlook the condition of those items.
In the end, do a BCAA inspection, but don't take their word as gold.