This is how I picked up a lot of my takeaway meals when I was travelling through the States and New Zealand. I wanted to avoid using disposable plastic food containers, cutlery and carry bags for obvious environmental reasons but also because of health concerns about plastic leaching into food.
Anytime I ordered a meal, I would just hand over my stainless steel tiffin box and ask if I could have my food stored in there (BTW, that's a lovely Thai meal in the photo). I thought I'd look somewhat dorky but restaurant staff were always so accommodating.
Taking your own reusable containers and cutlery is easy and reduces so much unnecessary plastic packaging. If you can try and do small things such as this, it will make a huge difference.