About storing syns, as a general rule we are supposed to have up to 15 syns per day. Say you had a special occasion next Saturday,you could save so many syns per day to use on Saturday. This isn't something I would recommend doing weekly. But if you blow 70 syns in one night and have a weigh in soon after,I'm not sure what kind of loss you would achieve. It's far better to get into a new routine of eating / drinking when out ,so your still on plan. At a BBQ you could have any free fish/chicken no skin/meat no oil. Salad,fruit etc all free. Limit one or two vodka diet coke/lemonade or Bianco diet lemonade both are 2.5 syns I think per measure. Or stick to diet drinks.
Saving syns up and still having that blow out naughty night regulally doesn't really encourage Ypu to change your habits that brought you to sw in the first place. It's hard but worth it. I took a chicken salad to a christening last week instead of eating buffet. I ate a piece of carrot cake, drank diet coke. And used less syns till weigh in and lost 2 LB. X