Property transactions vs GPA.

Sir, one of my client is entering in to buy one plot worth of Rs. 80 lakhs from the GPA holder. So, as per the recent SC Judgement, any transactions that are executed by the GPA is not valid, but still in the field/market, people are not very cautious about that judgment and entering in to such an agreements for sale /sale deed through such GPA’s. Kindly advice on that sir.