You'll call forth the legendary dormant beast of HSA! That's hot-side aeration - introducing oxygen into the wort which could cause some compounds to oxidize.
At least, that's the myth. HSA is a bit like santa claus, and autolysis, which although real, rarely affects homebrewers.
If you splashed the entire wort like this then there's a good chance the beer would oxidize quicker. But if it's just from the first runnings into the BK, then you don't need to worry. Using a hose to quietly transfer wort between the different vessels is considered good practice.
Just some conjecture now - I don't have any hard facts to back this up, but perhaps the reason that HSA is not common for homebrewers is that we boil the wort quickly after collecting it - usually within an hour, often much less. Once the wort is boiling, any dissolved oxygen is driven off. With commercial breweries, I believe it takes much longer for the brew to reach a boil, and so there is more time for the dissolved oxygen to bind and oxidize. Just a guess.