A tied dog has no options
The core problem with tying a dog outside a shop is that the lead removes every choice he would normally use to keep himself safe. A loose dog who is frightened can move away; a tied dog cannot. If an off-lead dog rushes in aggressively, your dog is trapped at the end of a short lead with nowhere to retreat, and fights that would never happen between free dogs happen between cornered ones. The same applies to people: a friendly dog may lunge with enthusiasm at a passing child, and a nervous dog who would normally back away from strangers reaching for him cannot back anywhere.
The lead itself becomes a hazard. Dogs circle, and a tied dog wraps his lead around the post, the railing, or his own legs until he is held tight against it — panicking, choking against a collar, or injuring a leg in the struggle. A lunging dog can snap a worn lead, pull a lightweight signpost over, or hit the end of the lead hard enough to hurt his neck. And a determined dog can chew through a fabric lead or back out of a loose collar in the time it takes to order at a counter.
Theft is a real, quick risk
A tied, unattended dog is the easiest dog in the world to steal: one person, one unclipped lead, a few seconds, and he can be walked away by someone who simply looks as if he belongs to them. Purebred, fashionable, and friendly dogs are at particular risk, but any dog can be taken for resale, breeding, or worse motives, and a dog tied in the same place at the same time each week is a predictable target. Even where theft is not a concern, well-meaning people sometimes untie a dog they believe is abandoned or distressed — leaving you with no dog and no idea which direction he went.
Weather, traffic, and what is within reach
A tied dog waits where you left him, in whatever arrives: full sun with no shade or water, sudden rain, a dropped ice cream, broken glass, spilled fuel, or food scraps he should not eat. Posts outside shops are usually beside roads, so a startled lunge puts him at the kerb's edge. He is also within reach of everything passing — bicycles, scooters, pushchairs, other dogs on long leads — with you inside and unable to judge any of it.
The better options
Plan the errand around the dog rather than tying the dog around the errand. Shop at dog-friendly stores where he can come inside on a lead. Use a click-and-collect locker or a drive-through where he stays in the car with you, where that is safe for the weather. Go with another person who waits outside holding the lead — a held lead is a completely different situation from a tied one, because a person can move, intervene, and give the dog company. Or simply separate the two jobs: walk the dog, take him home, then shop.
Identification is the backstop for the scenario tying up creates — a dog suddenly loose or taken with nobody who knows him nearby — and KinsLe's Pet Pass gives your dog a verified ID card holding his identity and your contact details, easy to show to anyone who finds him or to the authorities if he is ever taken.