I guess in some circumstances, there could be some siphoning. In the old Chevy small blocks, no ADBV was specified, and they were base end up. Technically, in my old LTD, with a sideways filter, the original specification was for a filter that had no ADBV, the CFL1, but with the FL1A as an upsell. Of course, most every cross reference to that these days will have an ADBV, though there were some applications that technically didn't call for one.