If I enter Canada without a passport on a big lake and then re-enter?
If I enter Canada without a passport on a big lake (such as Lake Saint Clair) and then re-enter the USA will I be arrested? Without any effort to clear customs yes you probably will be arrested or at least detained for a good while. If you are a U.S. citizen you do have a right to enter the U.S. but you will be detained until your citizenship is established (to the border officials satisfaction). Without a passport that could take quite some time and effort and at the end of it all you could face a fine for not reporting your entry as you were supposed to do. (You were also supposed to report to Canadian customs and would have been in serious trouble there too if you were caught. Your question presupposes you were not but that is being rather optimistic.) If you are not a U.S. citizen you could be in very serious trouble, including facing jail time, for entering the U.S. illegally.