We have a Nissan Leaf, I must admit I noticed that the security seemed a bit lax.
It's a great car and pretty quick nippy car, but the lack of App security is unacceptable.
The app itself used to fail for days - often when it was very cold or hot, presumably because everyone logs in to preheat their car using their heated wheel, seats and main climate on these frosty mornings.
There was a major app update recently, with a new UX and GUI, So I am a little surprised it didn't get sorted out then!
That said,
I still prefer driving the Nissan to driving my E Class Coupe on anything but long motorway miles, but the other half has it for her daily driver! :D
The climate will come on to a preset temp - you cannot change the temp in the app. Would take quite some time to drain the battery as the climate on the Gen 2 Leaf as it uses a heat pump and it very efficient, unless the outside air temp drops below 2-4c - In which case it uses a heating element.