"s/he" is just short for "he or she"...
IMHO the people who registered those domains deserved to lose them - just like people registering "UK domains " under .uk.com and .gb.com.
If you want a UK domain, it has to end in .uk - and even the most basic research would reveal that fact.
Perhaps P T Barnum was right [en.wikipedia.org] (even if he didn't actually say those words)
If a big enough registrar went in to administration/bankrupcy, it's most likely the customers would be sold off to another registrar.
I've had to use Nominet's Tag change procedure [nominet.org.uk] to recover a domain name that was in limbo went a UK registrar went bust. The customers (and their domains) were in the process of being sold to an alternative registrar with whom I had no wish to do business.
I've used the Nominet procedure to recover a .uk domain from a registrar who refused to deal with me unless I paid a disputed invoice - despite the fact that the invoice was for a hosting package on a different domain, not the .uk domain name in question.
I've dealt directly with Afilias and Tucows to recover a .info domain from a Tucows reseller who I was in dispute with - they refused to release the domain name until I paid up, this is against Tucows reseller T&Cs so after a lot of back-and-forth Tucows released the domain to me behind the reseller's back.
My approach to life is that nothing is sure PERIOD.
Life and business are full of uncertainties, but if you want to get on you have to learn to deal with this.
If you're looking for a cast-iron certainty way to hang on to a domain - bad luck, there isn't one.