The responses have a lot of clues that need to be picked up on.
I have a 2004 Cooper S. I don’t know how different the dash warnings are on the 2009, but 1) I don’t think that I have a “service light for a regular inspection.” 2) I do have a specifc light for brake wear. It is controlled by two brake wear sensors as acknowledged by AlanY. There is one at the left front wheel and one at the right back wheel. I do a lot of highway driving, so I didn’t replace my brakes until between 85K and 100K miles. That 30K miles sounds too soon for brakes, from my experience. Check your manual and determine what that service light indicates. And, see the manual to determine whether you have a brake service light. If you do, and it hasn’t gone on, then it is unlikely that the brakes need replacing. Don’t worry, when the light goes on you will still have a safe amount of pad left. You should just go and get the brakes replaced in a timely manner after that. I agree with Caddyman that 30K on the brakes should not regularly warrant a rotor change. There are specifications for rotor wear. The thickness can be measured and it can be determined whether turning the rotor is a viable option. Finally, front and back brake pads usually do not wear out evenly. Only one axle set may need to be replaced before another.
On the other hand, your dealer might be right and you are due for brakes. And maybe the other commentors are right about brake pads on sports cars, etc. Personally, I don’t see the logic about soft brake pads causing greater rotor wear. Does that mean that hard brake pads would cause less rotor wear? Wow!
I don’t trust your dealer. I recommend that you have someone else look at your brakes. It’s pretty easy to do, and it would not hurt for you to know how to do this yourself. There are two pads around each rotor. You should be able to see the outer pad without even removing the wheel, if you have alloy wheels. But you also want to see the pad on the other side of the rotor, and usually you have to remove the wheel. Inspecting one front and one back wheel should inform you whether the MINI needs brakes.
If you don’t believe any of this or if you want to get more information, go to MINI2.com. This is a MINI enthusiast site where you can ask questions in their forums. You can gain a lot of good information there, and it has saved me money.