Someone I used to work with had a Lexus and it sounded pretty similar to what you described for Mercedes. First time she called to schedule annual maintenance they offered her a spot on a day she couldn’t take off of work and they were like “that’s fine, we’ll pick it up the night before and drop off a loaner - call us when you’re home from work and we’ll come switch them back”
Although I guess that kind of support is less relevant with an EV because there’s much less scheduled maintenance so you only really need to go back if something legit breaks.
I’d assume you set it up in a way where you have to actively switch the direction to avoid this - would be a pretty big oversight if they haven’t thought of that before bringing these things to market
I guess that part is going to depend hugely on location - I’m in New England and have whole home AC but I don’t think I get above 35kWh/day in peak summer. Seems like the Lightning would be a pretty ideal backup solution in my case; extended range battery holds 131kWh, so theoretically I could run off that for almost 4 days if it could supply enough current to keep everything running.