Re anti theft of e-Trike outside grocery store.
I went through this exercise recently and the criteria I found relevant was,
The e-Trike should be very very easy to lock up so it doesn't go away, either by parking lot commandant or a thief or joyrider.
The lock up should be really really obvious so no-one inadvertently breaks spokes etc trying to get it away.
The e-Trike should have a parking brake or two so it will not roll unattended.
The electrics should be disabled until unlocked again and that should be obvious too.
The cargo compartment should also be either lockable or covered to deter opportunistic stealing of potatoes. :wink:

The lockable compartment makes a great place for batteries.
This is what I came up with and it takes a bit of doing but works very well.
A key operated electrical switch is securely mounted prominently on the head stem or handle bars.
A steel handle bar is required preferably as it needs to have a welded modification done to it. The mod could be done in Alum if an alum welder can be found, otherwise it could be done with rivets etc but would lack the same level of security.
The modification makes securing the E-Trike temporarily to a post or bike parking hoop extremely easy and obvious. A flexible cable such as found on cable bicycle locks and some motor cycle locks is inserted into the handle bar and retained at one end by a heavy duty collar or collets welded into one end of the handlebar so that the cable may slide out through the collar or be pushed in easily at will.
Either a swaged loop and padlock is used on the exposed cable end or a fitting that replicates the bicycle cable lock male part is securely attached to the bicycle frame so the key locking part of the cable lock which extends from the handle bar end may be attached to it and locked.
This system allows all the enabling and disabling to be done while seated on the e-Trike, which is the same convenience as sitting in a gas guzzler. It is also really obvious to an observer that there will be no quick get away today unless keys are in hand, same as a gas guzzler.
There is no handling and separate storage issue of the cable, it is at hand whenever needed.
I have found that tricycles are generally welcome on the footpath wherever there is enough room for other footpath users to navigate, and being attached to a bicycle parking hoop is an excellent way to prove a point of acceptance in an area.
Alan