I have never tried your pool, but are you sure it is actual pool hoppers and not people who just setup your pool as perhaps one of their backup options in case their primary pool were to go down?

I primarily point my miners at Ethermine where they normally stay, but every once it awhile they fail-over to one of my backup pools, such as Nanopool. Since the mining software periodically rechecks the primary pool to see if it is back up, I may only mine on the backup pool for a short period of time before the hashrate moves back to the primary pool.  I would hate to think this sudden inflow of hash power to my backup pool would be considered pool hopping and be penalized for it.