I was reading this question: Could the potion protecting the horcrux have been drunk by multiple people?
And noticed a comment by Xantec: "Well, a lot of muggles or squibs then".
Is there an official reason in the book as to why that couldn't be done? Meaning, bring one Wizard and a team of non-wizards (or Squibs if you are worried about statute of secrecy) into the boat with you?