Do sensors conflict when there are multiple gateways?
In general, even if more than one Gateway receives a signal from a given Sensor, the Network Server will automatically eliminate duplicate packets. Multiple Gateways should not present concerns provided the devices have been provisioned to only one Network Server.
When using cloud services such as machineQ or The Things Network, each of the Gateways is forwarding their packets to the same place (the cloud service's network server) and duplicate Sensor packets are handled properly.
When using a stand-alone Gateway with a built-in Network Server, any additional Gateways should be configured to serve as packet forwarders to the primary Gateway running the Network Server.