Can we somehow prevent this from happening again? Because nobody thinks about prefixing when contributing new rectors.

Thanks 👍

The first choice would be PHPStan rule

Do you know if there is such a rule?

If it would, I'd look for it here: https://github.com/symplify/phpstan-rules/blob/master/docs/rules_overview.md

There is similar for method calls: https://github.com/symplify/phpstan-rules/blob/master/docs/rules_overview.md#requirestringargumentinmethodcallrule

It can be duplicated and instead of MethodCall the New_ node should be used.