Outside of the flying school environment, VDO, Hobbs or tacho time is seldom used.
(VDO or Hobbs time often run while ever the master switch is on and oil pressure is present, thus maximum dollars for the school.)
Instead, most times are written down as "Off Blocks - On Blocks" or "Engine start - Engine stop" for flight time, and "wheels off - wheels on" for M/R time.
Airlines and GA charter usually document these times in a flight log or "Deck Log".
Where a suitable documentation method is not in use, e.g. helicopter mustering, a flight hour recorder fulfills the means to record the time.
Most panel mount Garmin GPS have a "Trip Time" page where Ground speed above a user specified value (usually about 50 kts) is recorded as flight time.
I've seen instances of pilots "losing" or having had stolen their log books.
Perhaps so as to create a new one with sufficient multi or whatever hrs was needed for a particular purpose?
Not sure who goes around stealing log books and what their market value is.
CASA audits of AOC holders will cross reference company flight records, maintenance release entries and pilot logbooks.
Heli and Ag work will often involve correlation of fuel purchased vs hours claimed to have been flown, this caught out at least one operator I know of.