sounds like the babies were having cows milk for all their feeds and eating salty foods. Bread has around 0.5g of salt per slice so it is easy to go over the limit just by having 1 slice of bread and some cheese and beans. A small amount of cows milk in cereal is fine for a baby over 6 months as long as the main drink remains breast/formula milk
It is a worry, but just wanted to give you a giggle as I don't call that paranoia. Paranoia is me worrying that DD could be harmed by the salt she imbibes just by licking or gumming down on my finger/hand, etc. as she constantly does. I honestly do worry about this! In hot weather I'm very salty LOL.
I was just already a bit worried as she eats quite a lot of cheese so was trying to limit salt intake a bit, but it seems to be in everything these days, there was a surprising amount in the yoghurt I was giving her too