Prior to C24, visitor status were given Pre-PR credit so long as they have evidence of "temporary residency" in Canada, for example, name on lease. Spouses on visitor status awaiting for spousal PR were given credit. Once pre-PR credit is allowed under the new law once passed, those on visitor status along with study and work visa will be able to claim credit. My wife would have been given pre-PR credit under visitor status towards citizenship as told by CIC officials at her PR landing appointment (she landed before C-24). People who came here on visitor status (tourists) usually don't have proof of "temporary residency". Spouses/common law partners on visitor status do.