At the end of the day, it's a free reading. Some things will be accurate, some things, not so much. It is still another perspective washed ashore from a sea of many paid for perspectives.
I've done this before and the free reads were awful and underwhelming. Nothing resonated, nothing fit my situation, the question wasn't answered, the reader was a novice at card reading no less, so I thanked them and moved on. We already know a horrid reading is going to be a possibility, but perhaps, just perhaps something may play out in the reading that does some good, or leads us somewhere, yadda, yadda. IDK, I haven't found that really good, special free reading yet, but it doesn't mean it won't happen. I suppose optimism is key, perhaps?
I always ask for the brutal truth and give feedback, only if the reader asks for it and I usually just make a list of things and say this is the list that was right, this is the list that was off. Just so they can see how they interpreted the cards and perhaps think of ways to create a better reading in the future for others. The reader can decide for themselves if it was horrible. I don't have to tell them that, since I didn't lose anything but time, but so did they.
It's all a crapshot, regardless.