We did a shopping trip last time and never again. The store wasn't laid out like I was used to at home - what we thought would be a fast trip took twice as long. Simple things like regional branding were problematic. 45 minutes in and out - it would be faster to check a bag. Plus we ended up with a poor recommendation for a store - we ended up at a grocery store on the way from the airport and it was a pit! How much toiletries can you be talking about? The hotel has shampoo. We bring toothpaste in a sample size, toothbrushes, a brush, and a sample size deoderant, plus the all important sunscreen!
We do, however, know we will be buying a tshirt for the kids on site, so we don't necessarily pack complete sets of clothes. I'm the "queen of the carryon" (or was before I had kids - now I need my own caravan of camels to get through the airport). I do understand the desire to pack light.