To take this idea of drilling holes to stop a crack continuing to its conclusion, it would seem that if I own a piece of Monart (or other glass for that matter), which has a number of cracks in it, the answer is to drill 5mm holes at either end of all of them (or at least the ones chosen as 'at risk') - thus producing an item that would be more suited as an impliment in the kitchen to strain the veg's? I seriously think not!
Just because a reputable restorer, such as Wilkinson's, suggested this invasive practice as a means of repair, it does not imply that it is indeed Museum practice. I would go further and suggest that this method of "repair" is a hang-over from the days when staples were used to put together either ceramic or glass items. The item in question would be drilled on both sides of the crack (or break), at intervals, and a staple inserted to hold the vessel together. It is frowned upon by museums - and was long ago left behind as a means of repair. Nowadays, any repairs untaken in a museum have to be reversable for a whole range of reasons.
The idea that drilling holes in an item as a repair is also a misnomer in my opinion. I can see that putting something back together is a repair, but scarring it with holes............?
It maybe that in certain circumstances that this method might be considered as a means of curtailing a crack, however I think that I would rather let time take its course as I would find the holes in an item frustratingly irritating.