relock should only occur if its necessity was confirmed twice

[lneuhaus]

The dominant source of delocking is a temporary unlocking (someone smashes on the table or abruptly opens the door) which is however often recovered by itself. However, if a lost lock is detected, the sequence is restarted without hesitation, thereby hindering a 'natural lock recovery'. More importantly, since we only sample a fraction of the time to check for islocked (1% of all data), we should directly enforce a robust unlocked condition before relocking.