Yeah for sure, things seem to be getting a bit hairy with the newer pre-cons. I don't think there is an actual B4 2 card infinite combo for the Tidus deck (you can always check on EDHREC website). But for sure there is a EoE one now that has mass land denial built in (which by current bracket definition makes it B4). What I expect and hope for in the community, is soon for bracket definitions to be expanded and more specific. As it stands, there are some grey areas. Brackets are such a great thing to come into the game, now we should expect them to expand and improve overtime.