How is this even vaguely, conceivably possible?
In no particular order..
- Shit UI. Confusing confirmation prompts.
- Shit UI. No confirmation prompts at all.
- Shit UI. An overabundance of (confusing) confirmation prompts lead to learnt "click through" behaviour.
- Shit UI. Difficult to set up and use record filtering.
- Poorly trained staff, because outsourcing to the cheapest bidder is always a good idea, not setting up weeding params correctly
- Knackered staff, because outsourced staff being flogged into the ground to keep costs under control, not setting up weeding params correctly
- Coding errors. Filter to weed out candidate records is set up (apparently) correctly, but code using the search params is shagged.
And, of course, a combination of one or more of the above.
Oh, and one for the tinfoil hat brigade. It was deliberate. Someone wanted a particular record disappeared and an "accidental" deletion of many tens of thousands of records is a good way to hide it. IIRC this is the underlying idea in Agatha Christie's, "The ABC Murders". The real target's killing is hidden and the identity of the murderer by swamping and misleading the investigators with a series of killings.
ETA.
And even if there were sensible, easy to understand, confirmation prompts there's no sensible and quick way that I know of for reviewing a batch of 150,000 records to make sure you've selected the *right* 150,000 records, You have to trust that the the process for selection is correct.