mine is not specifically mentioned, but had the same answer.  The way to test this is do a track day and crash, then let us know how you get on

.  I think you may win but as said earlier, it is down to test cases.   
 Also, I think it is part of your obligatory duty to advise anything which is not 'normal' for your ins policiy - otherwise it may be void or subject to lower claim payment.  Track days are not normal - I have been riding for a fair few years and recently did my first. 
 In an ideal world, it would be like communting - you either include or exclude and your premium reflects this choice.  That way I dont have to pay for you to be covered.