Error handling in Scrum

I posted a question to Stack Overflow some time ago about how to fit error handling in Scrum. I re-read the answers and the first one got me thinking and here's how I could see doing it:

There is a "Defects" task in the Product Backlog. Size is estimated by past experience or just guesstimated.

During the Sprint Planning, a new task is created in the PB, which could be called "Defects for Sprint X" (X = sprint number). The Product Owner adds items to this, team could add some etc. After all the bugs that are planned to be fixed are added to the task, the team evaluates them for the task size estimation like they do for any other tasks. This task is set to the top of the PB and normal Sprint planning resumes.

The main "Defects" task can also be updated at this point to reflect the work that will be done during this Sprint, i.e. by decreasing the size of this task. It should also be updated for any other new developments, for instance once the bugs start rolling in, the size can be adjusted. This all has the nice effect that we have an estimation of one of the things that often gets overlooked.

This way we will handle the defects like other work that has not been completely planned yet. We have a rough idea of how much work should be left for this task but we can also follow our estimations over time. It should be worrying if the "Defects" task doesn't get any smaller during the consequent Sprints. A draw a crude picture of this process to illustrate the idea: