The principle of noncombatant immunity in Just War Theory would mean that a tactic that might injure the noncombatants should be avoided. The principle of proportionality (in jus in bello) would also means that the potential for collateral damage should be considered when discussing tactics. That said, these were pagers to be used by Hezbollah to recall Hezbollah operatives, so it seem unlikely that a Hezbollah operative would give his pager to his daughter for her use, for two reasons: (1) his daughter probably has a smart phone so why would she take the step back in technology and (2) this was a one-way communication from Hezbollah HQ to Hezbollah operatives, so it seems useless for noncombatants, even as Hezbollah defines the term.
It may be indiscriminate, but not dangerously so.
On the whole, I'd bet fewer people will end up being killed by mistake this time than were killed after the US Hellfired an Afghan taking his family out to get drinking water in 2021.