Good spot, no this was not intentional.
However, since the WiFi AP is generally only used for initial setup it’s not a major issue. Agree it would be best to play it safe and have network secured. We will make the change for all new emonSD / emonPi units.
For clarification, the current contents of /etc/hostapd/hostapd.conf on the latest emonSD emonSD-30Oct18 is
interface=wlan0
ssid=emonPi
driver=nl80211
hw_mode=g
channel=6
wmm_enabled=0
If a user wants to use the emonPi in AP mode the password should really be changed anyway. To add WPA authentication the following additional lines should be added to /etc/hostapd/hostapd.conf replacing <YOUR-PASSWORD-HERE> with the password of your choice.
macaddr_acl=0
wmm_enabled=0
auth_algs=1
ignore_broadcast_ssid=0
wpa=2
wpa_key_mgmt=WPA-PSK
wpa_passphrase=<YOUR-PASSWORD-HERE>
rsn_pairwise=CCMP