Say no straw by default. If you need one for medical or accessibility reasons, carry a stainless steel or reusable silicone straw.
A plastic straw weighs about 0.4 g, so refusing three a week saves around 60 g a year, small in mass but a top beach-litter item. The bigger finding is chemical: a 2023 Belgian study found per- and polyfluoroalkyl substances (PFAS) in 90 percent of paper straw brands, most bamboo brands and some plastic and glass ones, and none in stainless steel.
The catch: some disabled people need bendable single-use straws; venues should keep them available on request rather than removing them entirely.