This should go without saying.
Not only is the theft of the item immoral in the first place but all of the problems that follow suit when an unknowing person purchases the hot item and the law comes a calling, etc...etc...
If it's discovered that any of our members are knowingly dealing in stolen goods your account will be suspended until wrongs are righted and you change your ways. How that information is gleaned by site admins is solely on your reputation and your perceivable actions.