The difference in expected utility from showering (either during a lightning storm or not) is minimally affected by the choice to postpone it. That's why I'm content to call it a binary rule.
The choice of showering/bathing at all has a different risk profile, yes, and also a different expected utility. Comparing the two is a false equivalence.
Statistically speaking: our kids (and their parents) simply enjoy watching storms, and we all choose to shower when the risk of lightning is zero. That choice maximizes utility, as our subjective enjoyment of the light show isn't diminished by postponing something as pedestrian as a shower for an hour.
But its still a massively better approach long term rather than making up some hacking project, quadruple that if one owns the place. I mean sure its nice to see such creativity, but in our lifetimes how often do we see some... lets say a bit different folks being obsessed in one topic, neglecting all other aspects or much simpler, yet less 'hacked on my own' solutions.
I mean it literally, one example out of endless sea - a peer making some VR game about collecting virtual balls by vacuuming over them in pacman style, across whole apartment, so kids do the work. Instead of learning children to accept the suck a bit since life will bring you millions more such situations, man up and just do it, without additional external motivation and hand holding. But he wanted to play around with tech primarily, not thinking much about potential consequences (kids outright refusing activities that aren't fun and strengthening this mindset). Of course that vacuuming is also pretty crappy at the end, instead of thinking 'there is corner / weird place that I should cover too', they just run quickly through all virtual balls, missing the core reason for vacuuming.
I had to look it up, because this seems like a pretty unrealistic fear to me. What I fond:
> less than 1 in 1 million chance of being struck by lightning directly or indirectly
> One-third of all lightning injuries occur indoors.
I'm pretty terrible at statistics, but I think we can assume that there's a less than 1 in 3 million chance to be injured by lightning indoors.
But lightning related injuries indoors could also be from a window exploding after lightning hits a tree outside, or a fire related injury from a lightning strike to the house.
So what's the chance of being hit by lightning in the shower? And then being seriously injured?
Snopes lists 4 examples of people being hit by lightning in the shower, spread over 20 years. All of them with minor injuries. The chance of major injuries is also much lower than with a direct lightning strike.
So finally, is the 'safe to shower' thing useful? I'd say that making this is probably time that could've been spent on more useful safety related things.
Also, if it's just 'is it safe to shower?', it ignores tons of other dangers inside the house during thunder storms. Touching any tap, corded appliance, concrete wall or floor or being near an outlet is just as dangerous as being in the shower and none of those things are particularly dangerous in the grand scheme of things!
Not to disagree with you general point, but applying general risks to specific situations is not proper use of statistics. Once a thunderstorm is on, the risk just multiplied from the baseline risk for the people in the area. And it grows again for people who take a shower.
This [1] is the best I could find with a quick search, admittedly far from ideal, but it has some numbers to start with and might help to locate better data.
The choice of showering/bathing at all has a different risk profile, yes, and also a different expected utility. Comparing the two is a false equivalence.
Statistically speaking: our kids (and their parents) simply enjoy watching storms, and we all choose to shower when the risk of lightning is zero. That choice maximizes utility, as our subjective enjoyment of the light show isn't diminished by postponing something as pedestrian as a shower for an hour.