5. Use a padlock in the EVSE handle and/or lock the unit with a chain through the 4 holes. Master Lock #630D is a combination lock that has no keys to lose and fits well.
I've been pretty paranoid about combination locks since one failed on me in the locked position. Fortunately it was a braided steel rope laptop lock and I just happened to have a pair of dyke cutters with me, so I was able to eventually cut the cable a few strands at a time and free the laptop (I carefully cut the lock from the laptop at home later with a Dremel fitted with a cutoff wheel). Anyhow, since then I've gotten into the habit of always making sure that combination locks unlock with the expected combination before using them - I figure if it works then, the chances of it failing on me after just a few hours of use are pretty slim.
So I did need to lock my EVSE down this weekend and, sure enough, when I went to check my locks (same model as above) one of them did fail in the locked position. It would have been very troublesome had this happened with the EVSE either locked to the car or the other end of the chain I use between the two locks locked to a piece of infrastructure.
Just putting this out there as an advisory - double check your locks before using them!