The FAA PIC is the issue, rather than solo. FARs allow you to log pic time if you are (a) PIC, or (b) sole manipulator of the controls of an aircraft you are rated in. So dual received by a PPL holder can be logged as PIC by both. You can also fly under the hood with a safety pilot (nominated as PIC) and both legally log PIC. Obviously these hours are weeded out by other authorities. What's the score in Canada?