Ive always thought of the flag being owned by the people of Scotland and what ever they want to add to it ..say with text or images is a show of pride of the saltire
even if its somewhat misguided and not thought out properly

i purchased a old navy signal flag which i believe is navy speak for "Mike|MIKE| My vessel is stopped; making no way"

but it was the only good quality cotton heavy weight flag with brass fixtures i could find that remotely looked like the saltire rather than buying one of those cheap looking poly flags (all i need now is a few hundred acres and a flag pole to hoist it up )