Give me 4 hours for the iPad to get enough charge in it to turn on and I'll verify on iOS 7.whatever the latest is.
You been busted watching a bit of blue Julian?
Long press on Chrome icon to bring up close button
iOS 7 users swipe the app upwards to close. Don't think iOS6 had the "multitasking" (I use that word loosely).
However, swiping the app up to close, does indeed keep the incognito tabs open. It also does it for a non incognito window. It also does it in Safari. Maybe they don't actually close, or they save their state, so closing the browser doesn't actually close it...