If someone lets you use their computer, and it needs some updates installing – assuming the owner isn’t there to ask – should you do it?
On the one hand, it’s none of your business. It’s their computer, their responsibility to update it. Just say “no” to the pop-ups and continue checking your email. Maybe they know what they’re doing, and have actively chosen not to run the updates: they prefer the version of the program they’re currently running, for example, and are holding off from upgrading to the latest one.
On the other hand, perhaps like most computer users they’re just hopelessly technologically illiterate and don’t realise they’re supposed to say “OK” to all some of the pop-ups that appear every time they boot up. And what if some of the updates are urgent security patches? Without them, the machine could be hacked, infected, recruited into a botnet and used to attack other systems. Like a child without a measles vaccination, increasing the risk of epidemic in the wider population, every second this computer isn’t updated puts every other computer in the world at greater risk. It’s not just acceptable, it’s your duty to update.