Among the many materials used for paver joints, polymeric sand fills the spaces between the pavers, tiles, and natural stones. Paver sand, hardscape sand, jointing sand, are all terms used to describe it.
Manufacturers add specific additives to jointing sand, which is composed of fine grains. Treating polymeric sand with water compaction explained in Section 1 is not sufficient. It will leave the pores.
For sand or polymeric sand to settle in the joints between pavers, the vibration of the compactor is critical. The vibration is what makes it look like the cracks are full, even though below the bridge they are empty/hollow.
Furthermore, vibrations compact the sand grains with fine dust between them, which further reinforces their joining.
To sum up, it is not recommended to not compact polymeric sand with a compactor. Use of plate compactor is recommended.