Well, that can cut both ways. In Petrov's case it worked out well, but 'ownership' of a problem (and the associated responsibility) in smaller settings can also work to bring out the best in people.

Separation of duties is a good principle, and wherever possible you should use it.

https://en.wikipedia.org/wiki/Separation_of_duties

But in the case of a single tech guy in a company there isn't a whole lot you can do in that direction, so it is best to clearly assign ownership and make sure that the people involved realize full well the consequences of a fuck-up.