PBL Items Re-estimated if a sprint is cancelled

How important do you think it is for the Product Owner to have an up-to-date view of the amount of work thought to remain?

Re-estimating an item is a considerable effort. What is the use of re-estimating it at this stage? My logic is, this item might not be the priority for the next sprint. It will make sense to re-estimate them, if they become the priority again. 

Sometimes teams can be too bureaucratic around estimation.

For the items that the Product Owner would like to be picked up again straight away, it might be acceptable for the Development Team to simply consider "What have we done or learned that would change our estimate for getting this item to a Done state?" If the answer is nothing, then further discussion around estimating that item is probably wasteful.

For other items being picked up straight away, the Development Team might simply estimate "given our other commitments, is this small enough to be Done in the Sprint?", in order to produce a realistic forecast.

For items that are not being picked up straight away, and therefore finding a place lower down the Product Backlog, perhaps it makes sense to treat them in the same way as other items that have a similar priority. As long as misleading estimates are removed, I think it's fine to treat this the same way as any item that has just been added to the backlog.

If the team tracks its velocity, it should also consider that a cancelled Sprint and the Sprint straight afterwards are likely to be exceptional, and might be worth excluding from their velocity calculation. This could reduce the pressure for having to re-estimate in a specific way.