May be I didn't understood correctly what you said...
Here is what I did :
- hook a usb soundcard
- launch Cross
- select asio4all
- configure asio4all to use only the usb soundcard
- play a track into Cross
- open the preferences/audio/control panel from Cross
- do nothing onto asio4all
- close asio4all panel
Got a half second freeze and still running with asio4all on the usb soundcard.
As far as I know USB disconnect and reconnect would cause at least 2 seconds of dropout which is clearly not the case there.
Even if it reconnect Cross doesn't care because it has already switched to the default soundcard (WDM).