Why no dye bomb?
I still don't understand why cash dispensers are the least bit attractive to thieves.
Surely they should be designed with a large dye-bomb inside, that goes off should a cable connecting the cash dispenser to the foundations of the building be cut. Banknotes saturated with dye are pretty much impossible to spend, so after word got out, thieves would leave all cash-dispensers alone.
In fact inside a cash-dispenser, it' would probably be safe to use concentrated sulphuric acid instead of dye, which would turn banknotes into acid-charcoal slurry.