First off, ask that it be taken manually.
Second, insist that you are sitting on an exam table with your feet off the ground.
Third, make your arm "heavy" in the hands of the examiner.
If you do these things, and you're still hypertensive, you probably need treatment.
Automated BP machines are notoriously fickle, and will often stop at a "diastolic pause" giving a reading of something like "139/100" when in fact, the true pressure is more like 139/80.
Anyway, blood pressure is generally a cinch to control, and, at least on this side of the pond, really doesn't slow even a class one down too much once it's appropriately addressed.