I could be remembering it wrong, but I think I remember that they actually did suggest caulking off the edge of the tape. Not so much for sealing, but for tapering that edge and so that the edge of the sticky part of the tape is covered so it doesn't collect dirt permanently.
Again, I'd suggest spending some time with what they recommend. A lot of info there.
and lots of stuff on youtube showing what went wrong when folks didn't install it correctly.... (hint, big messes and lots of work to fix)
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