It. Does. Not. Work.
There will of course be people who coincidentally ate a curry and then had a baby within 24hrs but one, they'll be attracted by the thread title and you'll get a false picture of it working, two, at 40+ weeks pregnant it was imminent anyway and three, it truly is just coincidence. No study ever has found any link between pineapples, curry, sex, long walks, sniffing badgers etc and labour starting.
The onset of labour is a peculiar chemical reaction between you and your unborn baby. It happens when the baby is ready to be born and this is a wonderful thing. You cannot, nor would you want to make it happen earlier unless medically necessary. If it worked at all they'd ban all of these things in pregnancy.
You might find a handful of women who ate curry and then had a baby. You might also find thousands who ate curry and didn't have a baby. In fact you'll find large cultures of women who eat a lot of curry and have babies at various gestations right for them. And you'll find millions of women who sat/slept/ate cake/drank tea and went into labour. Because it does just happen when it's ready.
I don't think there's any problem with trying to make yourself feel like you're doing something to help per se. But it's always eating spicy foods and getting indigestion or sex you don't want or marching around doing lunges and women are on here daily saying they're exhausted with trying and it not working. Why can't people start myths about cake starting labour off? It's as accurate but more pleasing.
Pregnancy is on average 37-42 weeks and it's psychologically a lot more bearable if you don't get to 40 weeks and assume you're overdue and need to start forcing the unforceable.