One theory that I've read is that the guests (soon to be castaways) were obviously upset about having to be put out of their rooms for the remainder of the day. To help with inconvenience the owners of the hotel refunded a few guests who took their things and went to a different hotel.

For those who still wanted to stay in this particular hotel, and wait out the day's fumigation, they were offered a 3-hour tour. Worried about their belongings the guests insisted that the tour boat booked be large enough so that they can take everything they had packed for their various purposes.

Seeing as the unexpected fumigation, guest refunds, and now a tour boat rental, the hotel owners had no choice to go with the two lowest bidders in the tour boat business: Jonas Grumby and Willy Gilligan. Thus, incompetence during the storm, despite the courage, left them all stranded.

Fortunately, because of the fumigation, their situation was made far more comfortable as they were forced to have ALL their belongs for their vacations/business trips with them.

I think they just had late flights and say they had to be out/ check out of their hotel rooms by 11:00 , they had a lot of time to kill before having to be at the airport for their late afternoon /evening flights, (keep in mind this was the early 60's long before we had all the airport security and had to be there so much in advance before the flight ) ! Hey ,sure why not take a three hour tour, even if they had to bring their luggage along with them, better than being bored hanging around the airport for hours!!;)

I recall Sherwood Schwartz saying that he/the other writers considered having a cargo ship loaded with clothes and supplies go aground on the beach and the Castaways having a seemingly endless supply of stuff- but then realized that that would be TOO logical and it would be more comically fun for the viewers to wonder 'Where did they get THAT?!'

P.S. Among other illogical stuff, they NEVER came up with a reasonable explanation for how an entire tub of vanilla ice cream came to float by [UNMELTED!] when Gilligan wished for it. The Professor's attempt that it came from a passing cargo ship was rather lame inasmuch as the ship would have had to have been within FEET of the island to have dropped the tub in time for the tub to get intact to Gilligan (and why wouldn't any of the Castaways not seen or heard the boat much less have attempted to chase after it to rescue them had that been the case).

I was wondering how the castaways managed to shave or cut their hair. Did they happen to bring grooming kits with them? Or did the professor make razors/trimmers from seashells?

Randolph Blake is the answer to all questions. It isn't possible that it's a coincidence that all five passengers knew and disliked him, and that four of them confronted him on the night before the Minnow sailed. Blake must have enticed them to that place at that time.

I suggest that Blake arranged for his enemies to be marooned until some time of his choosing, and that he arranged for someone to monitor them and occasionally supply things. Blake then died on that fateful night, but his unseen minion remained faithful to his task, and kept the project running through year after year.

I was wondering how the castaways managed to shave or cut their hair. Did they happen to bring grooming kits with them? Or did the professor make razors/trimmers from seashells?

Lovey Howell chased "The Mosquitos" band members with a pair of scissors, and Mr. Howell cut (and buffed) blades of grass, one by one, with a scissors, so clearly they had those.

Wasn't The Skipper or Gilligan seen about to get a haircut? I don't recall any razors or references to shaving though.