Let's smell the coffee!
If we don't make an effort to tilt the scale artifically in situations such as these, juro, tell me what would eventually be the purpose of conducting a spey clave? Obviously, not to catch fish which lie in relatively protected areas in the middle of larger rivers...there will be no fish in those areas to catch. So, I guess the purpose of any fly fishing school or spey clave would be to teach the participants the fundamentals of casting, with the ultimate goal of being able to boast of how long a line he or she could cast...over barren waters, mind you. If that is what thrills one...to boast of how long a line he or she can cast...I think they are a performer, not a fisherman.
I would suggest that the presence of a seal, well upriver from the ocean, is itself an artificial situation. At least, it is here in the rivers I have been fishing for over forty years. An artificial situation brought about by the irresponsible actions of liberal do-gooder groups such as Green Peace and The International Organization for Animal Welfare which effectively put a stop to the annual seal hunt off our shores and caused a massive increase in the seal population. Killing a seal in such a situation as this then can hardly be classed as an artifical "fix". The situation that allowed it to be there in the first place is what is artificial.
I don't think it would be long before Walton's(?, I believe it was Walton's)premise that the anticipation of catching a fish arose even as one approached water that one knew had been fished out would very soon get a little stale. At least, I think it would for most TRUE fishermen. Perhaps not for "line casters".