Parking rear-wheel first: which sprocket to put rear derailleur in? So, I want to keep this from happening:



To that end, I like to park my bicycle rear-wheel first, which was discussed in answers to this question, where I'm taking the images from. Since almost everywhere I need to leave my bike the stands tend to be of the variety you stick your front wheel into (image below), I like to park my bike rear-wheel first and lock the frame to the rack. Most of the time, the rack has space for the rear derailleur either inside or outside the rack.



This brings me to my question: Should the rear derailleur be between the tines of the rack, or should it be outside the structure? In other words, which sprocket should I have the chain on when it goes to the rack? For purposes of this question, please assume I don't have a kickstand.
You're unlikely to get the derailleur outside the rack with much clearance, so the chances of knocking it getting the bike out again are quite high. It may even be possible for someone to bump the back wheel and bend your derailleur. 

Selecting a bigger sprocket also puts the derailleur further forward. This is likely to improve the clearance around it but of course that depends how your bike sits in the rack.

Cross-chaining into a big ring and a big sprocket brings the derailleur even further forwards, but change out of this when you get going.

You may also want to invest in security skewers and/or an extra lock for your front wheel. Your local bike thieves sound like they have a surplus of bikes without front wheels.