I had read somewhere that wrapping potatoes in foil after cooking increases risk of bacteria etc growing should they remain sitting for a long time. Thoughts?

If you plan on serving the potatoes right away or immediately after preparation then wrapping the baked potatoes should be fine, just avoid holding the wrapped potatoes at room temperature for an extended period, say past a half hour for consumption; and cool before wrapping if holding in refrigeration, and consume withing two days. It’s always best to yield to safe practices. As always, follow your local health department guidelines for handling, preparing, serving and storing food items.