Maybe you could get thenewgreen to join you in Detroit. Not many races requre travel documents to run across the border.
If for any reason (for example, emergency, carrying a backpack) you are asked by CBP to identify yourself when crossing the border, you will be expected to present proper identification (WHTI compliant document). CBP actions may delay your re-entry into the U.S. Please note: it is not the intention of CBP to actively or randomly pull runners out of the race to review their documentation.
Please note, the Ambassador Bridge Company and Detroit Windsor Tunnel LLC policy is to prohibit liquids. Runners are discouraged from carrying items on these portions of the course as they may be asked to either inspect or drop them. However, at the end of the day it is up to the runner’s discretion.