Hey, I had almost the exact experience this past weekend. It is the Heritage Days festival here in Edmonton, and I attended with a delightful ex-Witness. We saw the JW's when leaving the venue (very heavily attended, lots of foot traffic), four carts, four Witnesses standing like statues. We observed them for five minutes, and there was absolutely no engagement with the crowds passing. With one exception. A gentleman approached them to engage in a little conversation. The JW's backed off! We collared the gentleman afterwards to get his impression. He found it surprisingly off-putting, as he has talked to Witnesses before and considered them to be friendly, moral people. He was shocked to think that the Witnesses there that day were there only to "put in their hours".
My companion pointed out that if the proportion of vulnerable bystanders is about one in a thousand, there were possibly 200 potential converts in that crowd! You'll be happy to know they will be safe from their Witnesses and their aloof approach.