Hi,
mostly reversed battery protection is required for household stuff requiring little current flow.
When powering an expensive current consuming device it should be double checked if the polarity is correct.
Here is a cheap alternative to protect curcuits up to 40V and 1A, the Schottky-Barrier diode PMEG4010ER (NXP semiconductor).
Here are some important data: VR=40V, VF (at IF=1A) 430mV (max 590mV), IR (at VR=40V) 10µA (max 50µA), part dimensions (body (SOD128)) 5X2.3X1mm (LXWXH)
Hans