It would be better if Jr Member requires 5 merits. Having 1 merit is really easy task. Also, it will increase the abuse a little more.
That's probably the next plan if 1 merit is not enough. It's one way to flush out the smerits from these abusers until they have none to send.
today i become newbie verry sad i think better if need 200 activity to become jr
This suggestion is only better for you. Without a merit requirement for Jr members these spammers would just farm activity then continue once they reach the required activity.