From the test, Marked Lane Spaces

[agr8zebra]

Opponents of the free thrower may never occupy the second marked lane spaces.

It is FALSE

Found a case book interp... Page 62 8.1.4 sit b

[Nevadaref]

Originally Posted by agr8zebra

Opponents of the free thrower may never occupy the second marked lane spaces.

It is FALSE

Found a case book interp... Page 62 8.1.4 sit b

You seem to be a fairly new official, certainly less than 10 years. That's not a criticism in any way, just noting it because it has a bearing on your perspective. Those of us who have been around long enough to remember when the NFHS went to the 4 v 2 player count along the lane and also reduced the number of marked lane-spaces on each side from four to three back in the 2003-04 season, recall that a comment was included regarding the rule change specifying that players could fill any space left vacant by the opponents other than the bottom two. So the answer to this question has always been clear for NFHS rules.

Lastly, the current Rules Book also gives you a clear answer on this:
8-1-4(f): "Players shall be permitted to move along and across the lane to occupy a vacant space within the limitations listed in this rule."