Apparently we can register as a liberal to vote in the upcoming leadership race. What does it mean if I register? What do I gain (besides the aforementioned voting) and does it place any kind of restrictions on me (e.g. am I prevented from doing the same with a different party)?
There’s no official public record of political party membership in Canada. No restrictions are placed upon you, but if you plan to run against one of their opponents, expect it to come up.
Note that donations are tracked and published by Elections Canada.