connect to mobile phone without pairing

hi there can any 1 help me ive got a DELL AXIM X50 pocket pc, i would just like to know, i got this device and i would like to used it to play tricks on my brothers through the bluetooth technology by connecting one of their mobile phones to my device and then using it to call the other. tried to do it but it never works cause they keep on finding out cause my device always pop up asking for their pairing permission, so if any one knowns a way that i can do this discreatly without pairing my device and my brothers mobile phone, pls let me know

[getsurfers]

It's known as bluejacking. See http://www.bluejackq.com/bluetooth-pc.shtml

If you want to play jokes, send calender notes between mobiles (via Bluetooth) with your device set to hidden.