I worked in a place where TOIL was given for working over hours, they had no limit on the amount of time that could be accrued,
I spent three months working stupid hours, trying to get a project finished, compounded by the fact my assistant was long term sick,
in the end I accrued nearly three weeks worth of TOIL, so I added a couple of days Holiday to it and put in my request for time off,
You should have seen my Managers face when I gave him the verbal heads up, it was as if I had just killed his mother, He basically refused it on the spot, claiming the two week rule etc.
At that point I swore I would never work for TOIL again, EVER.
I have since changed this to never working over a weeks worth of TOIL, and that I must be able to take it, before I accrue anymore.
but yes its a con, but has its benefits if you fancy a quick getaway with the missus, and don't want to use Holiday allowance.