Citation please for your claim about Estonia's EPIRB buoys. These buoys are always 'switched on' as it were, so that should they touch the surface of the sea, their GPS signal is activated. There is no reason to 'switch them off' and a manual 'switching on' in distress is not necessary as they are designed to activate themselves.
Yet again, you're making incorrect pronouncements on something you very clearly know little or nothing about.
If you'd stopped for even a few seconds to think about what you'd written here, you might have realised the fundamental & fatal flaw in your claim. It's a one-word flaw: batteries.
See, the beacons on these buoys ("boo-wees" to Americans

) don't power themselves by magic. And EPIRB buoys are not solar-powered - for several good reasons. So they have charged batteries within them, ready to supply power to the beacons when required.
If these beacons were "always switched on", as you claim, the batteries would have run down and died within days of renewal. Which is precisely why they are
not always switched on. And it's why they're only ever switched on if/when they're actually needed - ie when the ship is sinking.
Now, in 1994 there were two ways in which the buoys could be switched on if the ship was sinking: either a) they could be manually switched on by a crew member, or b) they could be fitted with a sensor which was capable of detecting immersion of the buoy in water (something which would only occur if the buoy was deployed by a sinking ship). But here's the thing: in 1994 these buoys with immersion sensors were a costly upgrade for those ships which had already been fitted with manual-activation buoys.
These immersion sensors were not mandatory in 1994. So, as (presumably) a cost-saving measure, the Estonia's owners chose not to install buoys with immersion sensors. Which meant, by definition, that the EPIRB buoys that were on the Estonia needed to be manually switched on by a crew member once they realised that the ship was going down.
And it's exactly this which prompted a change in regulations to make immersion sensors mandatory: the Estonia sinking showed that manually-switched-on EPIRB beacons were a liability - their obvious shortcomings could significantly hamper attempts to identify the sinking ship's position and optimise search & rescue efforts.