I looked into it and the non tucking isnt an issue. Modern homes have transitions from carpet to tile with no transition strip (or tuck) commonly. Also, the PL has an advantage of not spalling the concrete or coming loose over time. Overthinking things led me to worry.

Troy, I wasnt aware you could put vapour barrier directly on a slab. Dont you mean Dricore or the plastic orange corrugated underlay? The concrete must be allowed to breathe or moisture issues might happen afaik. Carpet underlay has a slight membrane on the side that goes down to keep the foam from wicking moisture out of the concrete I think. Not totally sure if that is its purpose.