It's a trust thing. Also a "better the devil you know than the devil you don't".
The most depressing thing I've ever seen in maintenance was a project that got sent into prod with 300+ known defects, they hired other people to fix the defects, when the defect count got below ~50 they bought back the same guy who had screwed up phase 1 so badly to do phase 2 for them.
The most depressing thing I've ever seen in maintenance was a project that got sent into prod with 300+ known defects, they hired other people to fix the defects, when the defect count got below ~50 they bought back the same guy who had screwed up phase 1 so badly to do phase 2 for them.