As amply stated by others, use common sense, observe, be situationally aware, and improvise.
Coil locks have always been my preference, with the ability to easily attach to a picnic table, a tree, two bikes together etc.
And be friendly and presentable for when politely asking a cashier to keep an eye on your bike inside a store for a few minutes. Be a good judge of character also in this regard, ie grandma selling raffle tickets outside general store probably is safe, a couple of shady looking bored dudes outside an urban setting, less so.
buyer beware, cyclist beware.