It is looking more like Israel (Mossad) managed to plant explosives in the devices. Manufacturer pleads ignorance, so not sure how else it could have happened.

As a side note, it is against international law to weaponize devices civilians might use. So you can't put an IED in a teddy bear, for example. I don't expect terrorists to pay any mind to that, but Israel is an actual nation that should be bound by those laws. "Booby traps" in pagers and phones appear to be forbidden. But they appear to have done it anyway.

It was very clever. But you're right: what if one of the devices was on an airliner, or a London city bus? Airliners provide cell service in-flight now.

Israel is managing to turn international opinion against them. The UN just voted against them (specifically their occupation of Palestinian territory). Any good will from the attacks last year appears to have disappeared. Not that most people are sympathetic to Hamas or Hezbollah, just that Israel continues to engage in atrocities and violations of international law.