In your BIOS if you disable wake on lan and USB it should ensure the system properly sleeps instead of jumping to the login screen.
Here are a few observations I've made about sleep stability on my Probook 450 G1.
1) It seems pretty successful in putting itself to sleep automatically and manually with Apple->sleep however closing the ldi is very inconsistent. I'd say maybe 50% of the time it fails to where the screen goes out but nothing responds and the power button isn't pulsating like a normal sleep mode.
2) Waking from sleep in 10.9.1 seemed to be fairly stable but has recently changed. I assume it was 10.9.2 upgrade but not 100% sure since I've constantly be futzing with things sine then. Anyway, it appears to wake just fine but then after a brief period of time (5seconds to 2 minutes) the screen just goes black and the HD trashes briefly and then nothing responds. I have to hold the power button down to turn the machine off and restart. After booting up again I noticed every once in awhile Clover attempts to resume from hibernation which I was hoping was a clue to the problem. However, even after setting hibernatemode 0 via pmset the problem still exists. Not really sure what else to try at this point.