Invite someone that set presence offline

Invite someone that set presence offline

Do u ever have experience like that? u have set presence offline but u always invited in a group chat by someone, u have block that person too but u have invited again.
You want to try this trick? here it is :

Use 1 nick with 2 contact list. login with nick that u want to use the contact list (nick A), when appear 'downloading contact list' press the back button, then login with nick that u want to use to invite someone
Create group chat as many as possible.
Each time someone left your group chat, invite again, again, again and again
When he/she set presence offline, in ur contact list he/she still online because lock with nick A when first login
Invite the target when he/she still on (not log out)