If there were a few more PM, it could be considered a scam. Five bucks is not such a sum that it can be noticed; asking several could get a good amount.
It's not like I sent PM before to gather $5 from different person but only for borrow $5 from someone and when I did get it then I stop. Now that I know that a simple PM could make people think that it is a scam shows me that I should stop doing it.
Just in case, just in case you forget one day that you ask one stranger for 5 dollars and another for 10, I will leave a neutral tag about your love for PM. You know, any scammer will always say that when he allegedly borrows from someone, he always intended to give it back. Don't believe me? Read the threads from shasan and his debtors.
Strangely, you don't ask strangers for money on social networks.