But is there any specific guidelines that state one can or cannot be DFd for marrying a non witness
berrygerry summed it up: "(Brazen conduct is anything not covered by anything else.)"
After she's been warned its pretty much up to the elders discretion.
My unwanted advice is as follows:
1. The sister should state to the elders that she will not marry the young man.
2. Continue to date the man of her choice privately while feigning a broken heart.
3. Start to fade. When confronted by the elders she should claim that she is depressed because of the breakup and the pressures of work/study/whatever.
4. When her fade is complete, switch congregations.
5. Finally marry her beau and live happily ever after, or discover after a couple of years that he was not the droid she was looking for.