Bluetooth Low Energy was designed as a low-power alternative to classic Bluetooth. However, the use of BLE in dense Internet of Things deployments results in high collision rates and wasted energy. To alleviate some of this contention, we present opportunistic listening, an extension to BLE active mode targeting IoT deployments with large numbers of tags and small numbers of scanning devices. For dense deployments of passive advertising devices, we present the design of Smart LaBLEs (BLE-enabled, electronic, de-centralized hubs), which aggregate multiple advertisements across similar products in a retail environment.