I understand your thoughts. My comments are not based on one individual. When things are left down to individual marshals at shoots to sort, none of them are going to want to look for an arguement about who can do what.
If you can't shoot all of the positions that a specific class requires, you should not shoot in that class (Only simple away round that is as has been mentioned, if you can't kneel, you stand. If you can't stand, you take the two 0's if you want to shoot in existing class) .
Done that way, there is no room for argument.