The 2" length of strings has been in the rules for a couple of years.
See link below
NFHS Rule Changes
The NFHS has delayed implementation of a change to boys lacrosse Rule 1-7-3 until the 2016 season. In the 2015 rules changes, Rule 1-7-3 was amended to read:
ART. 3 . . . Any strings or leathers are limited to a hanging length of 2 inches. All hollow crosse handles must have their open end covered with an end cap manufactured for a lacrosse stick. In both cases, the crosse shall not be considered illegal; however, it shall be removed from the game until corrected.
Any additional strings or laces (e.g., shooting strings, V channels) must be located within 4 inches of the top of the crosse. No more than one side wall string on each side is allowed.It should be noted that the first paragraph of Rule 1-7-3 will still be implemented for the 2015 season. Only the second, underlined part will be delayed until 2016.