Flirt Test is Effective
The answer is "NO" because body language signs are WAY too easy to be misused or abused.
There are a lot of books out there that state crazy things such as, "If a woman tilts her head at 45 degrees while looking at you from her shoulder and smiling at you with her legs crossed, she must be attracted to you."
This is utterly USELESS in my opinion. In fact, I really think it's all b@llsh*t.
My motto is always KISS, or "Keep it Simple, Stupid!"
I don't need to check 15 different body language indicators to see if a woman is attracted to me. I just do the "Flirt Test".
When I want to find out if a girl is attracted to me, I merely flirt with her a little bit. If she flirts back, then I flirt more.
I just keep testing the waters and raising the chemistry until she's all over me.
This works MUCH better than sitting back while "looking for body language signs", which is really passive AND useless.
Good Luck!