Using satellite imagery to fix street alignment:

Well, hopefully that title got some people's attention. I understand that satellite imagery alignment may be off, and that it is unwise to use it exclusively to determine objects' exact locations. In the area I'm primarily mapping at the moment (Vancouver, Canada) I find the imagery (BC mosaic) to be high quality. Mapped roads usually are bang on the middle lines of the imagery, the two correspond pretty exactly. Mapped alleys on the other hand often appear to be straight in the imagery, but have multiple nodes not aligned in a straight line in the mapped data. Some alleys are not mapped but appear in the imagery. Many alleys are located at slightly differently in the imagery and the mapped data. Additionally I've surveyed a few of the discrepancies and found the imagery correct, with the OSM data wrong. In this case it seems to me that the mapped data is poor, and I should improve it using the imagery. I think it is usually unadvised to alter nodes already in the database based on imagery, however in this case it seems to me our OSM data on Vancouver alleys is poor, and it is worth trusting the imagery. What do others think?