When you look at the same firms reporting US numbers you will see how far off they can be from real numbers that you and I have access to. Then that leads me to believe that their margin of error globally must at least be similar.

Google reports Android activation numbers all the time and I have yet to see how the numbers they mention are possible, given the updated stats of all Android products. ie. you can multiply out their activations and the numbers never fit with the total number of devices they also report.

It's entirely possible Samsung has sold 50m smart phones, but high improbable, if for no other reason that shipping a product into the channel doesn't mean it's actually sold. However many phones Samsung has out there in the channel now, they better hope that inventory gets to consumers soon. Because come September there's going to be a big reason for retailers and distributors to start returning product.