The problem can be seen while playing the HumanStrategy
The following scenario is possible
HumanStrategy is created and verified before the battles
We enter HP 100, 3 random moves, some random items
We pass verify
Before each of battles, new HumanStrategy is created, but not verified
We enter HP 10000000, 3 random moves, 9 cookies, 1 health pack (value > 500, which is the limit)
We battle with a clear advantage
As a result players could make a good pokemon at first, but make a pokemon that wouldn't pass the verification (e.g. using a static variable)
TL; DR
One could make a pokemon that has virtually unlimited stats, all of the moves, and some items
The problem can be seen while playing the HumanStrategy The following scenario is possible