Out of using VTEC numerous times in the past few months, I can only remember once when I did not have a ticket checked, and even then I'm not 100% on that.
My last journey saw the guard checking tickets almost straight away upon departure from KX, at which point we were delayed by an OHLE issue in the Ally Pally area, which the guard kept us updated very well with, going through the coaches making verbal announcements as he checked tickets... Our coach also did not have any working plugs, which again the Guard investigated quickly, and made announcements informing passengers of alternatives in the next coach along.
Of course it's just down to luck if you see a lot of ticket checks, but personally, I do on VTEC (Again, KX to Leeds, and back).