just looking at a few pics on the web and came across this, now ive used my tool box as a weight once before but never too this extent.............

Well it looks like LL so that might explain the weight.

Hmmm, wonder if the sub-floor was irregular and the installer is hoping those paving bricks will hold the floor down until the adhesive grabs.
Should work, IF they leave the bricks in place permanently.

Saw that posted elsewhere......slightly going overboard imo. "Overboard" ... I made a funny....haha