As long as the expired lemonade has been refrigerated and tastes okay and smells okay the expired lemonade would be safe to drink.
Lemonade should last up to 7 days in the refrigerator and will last up to 6 months or longer when frozen.
The expiration date of lemonade is just a general guideline as to the freshness of the lemonade and doesn't always mean that the lemonade is no longer good or safe to drink.
If you do drink bad lemonade the worse thing that will happen is that you get a stomach ache which will go away within a day or so.
But just smell the lemonade and if it smells good or it tastes good then it's safe to drink.
If it smells bad or tastes bad then you can throw it out.