Some client implementations wait only a few ms after sending a probe request while scanning. It might be impossible to get the frame out before the client leaves the channel again. If the client leaves before all probe reponses where acked this can cause the probe response to be retried quite often consuming even more airtime.
Therefore, the question arises. Is it possible to set a flag to not send more than 1 probe response retry to broadcast probe requests that contain a wildcard SSID?