A method for providing accidental stack join protection, the method comprising: connecting stacking ports (104A, 104B, 106A, 106B, 108A, 108B) of a first switch that is a member of a first stack and a second switch that is a member of a second stack and thereby connecting the first and second stacks (100, 102); detecting configurations of the first stack and of the second stack; the method characterized in that it comprises: determining whether the detected configurations indicate a stack configuration mismatch between the first and second stacks (100, 102), wherein determining whether the detected configurations indicate a stack configuration mismatch includes determining whether the first and second stacks (100, 102) are operational, whether a slot identifier is duplicated between the first and second stacks (100, 102), and whether a stack identifier associated with the first stack is different than a stack identifier associated with the second stack; and in response to determining that the detected configurations indicate a mismatch, inhibiting automatic joining of the first and second stacks (100, 102) and allowing the first and second stacks (100, 102) to continue switching traffic with their existing configurations, wherein allowing the first and second stacks to continue switching traffic with their existing configurations includes switching data traffic using existing layer 2 forwarding and layer 3 routing tables of the first and second stacks (100, 102), and wherein inhibiting automatic joining of the first and second stacks (100, 102) includes blocking the transmission of data packets and management packets not associated with stacking control and status between the first and second switches (104, 106) and allowing the transmission of packets associated with stacking control and status between the first and second switches (104, 106). connecting stacking ports (104A, 104B, 106A, 106B, 108A, 108B) of a first switch that is a member of a first stack and a second switch that is a member of a second stack and thereby connecting the first and second stacks (100, 102); detecting configurations of the first stack and of the second stack; the method characterized in that it comprises: determining whether the detected configurations indicate a stack configuration mismatch between the first and second stacks (100, 102), wherein determining whether the detected configurations indicate a stack configuration mismatch includes determining whether the first and second stacks (100, 102) are operational, whether a slot identifier is duplicated between the first and second stacks (100, 102), and whether a stack identifier associated with the first stack is different than a stack identifier associated with the second stack; and in response to determining that the detected configurations indicate a mismatch, inhibiting automatic joining of the first and second stacks (100, 102) and allowing the first and second stacks (100, 102) to continue switching traffic with their existing configurations, determining whether the detected configurations indicate a stack configuration mismatch between the first and second stacks (100, 102), wherein determining whether the detected configurations indicate a stack configuration mismatch includes determining whether the first and second stacks (100, 102) are operational, whether a slot identifier is duplicated between the first and second stacks (100, 102), and whether a stack identifier associated with the first stack is different than a stack identifier associated with the second stack; and in response to determining that the detected configurations indicate a mismatch, inhibiting automatic joining of the first and second stacks (100, 102) and allowing the first and second stacks (100, 102) to continue switching traffic with their existing configurations, wherein allowing the first and second stacks to continue switching traffic with their existing configurations includes switching data traffic using existing layer 2 forwarding and layer 3 routing tables of the first and second stacks (100, 102), and wherein inhibiting automatic joining of the first and second stacks (100, 102) includes blocking the transmission of data packets and management packets not associated with stacking control and status between the first and second switches (104, 106) and allowing the transmission of packets associated with stacking control and status between the first and second switches (104, 106).