I like the second one. I think we thought of that. It is simple beautiful answer, that it not able to come to issur because you never use it except for kavush.
I didn’t think of the first one, but who knows, maybe.
How about this: The whole piping is only a few feet of plastic tubing, so the entire volume of the tubing will be batul in the huge keg of beer, so it is darko to use bshufi?
Do we care that at the end of the keg it will not be batul anymore?
I think we may have had even more tzdadim.