I still don't unclip with multis but feel a bit more secure in the singles. It will only happen if you twist your foot whilst skidding, which is technique fail anyway. On the other hand, the instructions for the multi release cleats specifically state that they are not suitable for use in applications that require pulling up on the pedal (from the rest of the context they seem to be referring to jumps and such like, but even so.)
I still don't unclip with multis but feel a bit more secure in the singles. It will only happen if you twist your foot whilst skidding, which is technique fail anyway. On the other hand, the instructions for the multi release cleats specifically state that they are not suitable for use in applications that require pulling up on the pedal (from the rest of the context they seem to be referring to jumps and such like, but even so.)