Several of the pre-fab SIPs use something like a grate along the bottom (from what I've seen in pictures, I've never owned one), and in the early DIY SIPs I built I mimicked this by drilling holes in the bottom of the container that held the soil. It seems like the air gap/wick combination separates hempy from SIP, but I was not aware that the holes between the soil and the res was a defining factor in calling something a Sub-Irrigated Planter.
My first SIPs had those holes, but subsequent ones were patterned more after the Octopot, which I am not aware of as having similar holes (and I believe is considered a SIP?). In my current SIPs which use a fabric pot sitting on a plastic bin/res, there are no holes beyond the large one that houses the wick. I do maintain an inch gap between the top of the res and the water line, and I also use air stones in my res. It's possible that my air stones serve the same function as the holes would, but I think I'm hearing that other designs that don't have the holes also work?
The bottom line is that I consider my current design to be a "SIP", but maybe I'm misusing the term. Perhaps at least for the purposes of accuracy in our conversations, we should structure a definition of SIPs -- even if that ends out being a loose definition.