You plan your visit so your kids are with you in the safe part of the store, and you drop them off at the playspace when you're loading the car. You remind your kids that there's a bathroom in the playspace and to please use that rather than asking them to call you to come leave. You break your visit into 2 visits, select your items on the first day and come back another day to purchase them (It's not like w'ere talking about a pharamacy or grocery store or other store that sells things you need in an emergency). You leave your kids with Grandma. If your kid is young enough to be in diapers, they're likely young enough to be strapped into a stroller.
Almost any other store I'd be agreeing with you. I am a special educator, as well as a single parent. I know better than most that wonderful can parents can have challenging kids, and that wonderful kids can have challenging moments. I took my kid everywhere from infancy on, and wasn't one to expect him to be strapped down in his stroller every minute.
But we're talking about a situation with significant safety concerns here. A child who has a piece of furniture (in the box or not) dropped on their head can die. Running around at IKEA is not OK. It's not good parenting, just like letting your kid run in traffic is not OK even if they're tired or cranky or just acting their age, or you have flat tire you didn't plan for.
I agree with what you're saying, that's what I was trying to say should be done, only I was so tired after all the hauling yesterday that my brain wasn't working properly. IKEA is definitely one of the more family friendly stores there is, but I don't think they should allow small children running in the warehouse. Either make it a rule that small children be strapped in a cart, or have them be dropped off at the play area, or something. All it takes is one accident.
Another instance I saw yesterday, someone was pushing a cart with quite a few boxes on it, and then these 3 kids were pushing another cart with about 4 boxes on it. 3 of them, pushing it together, the oldest one looked to be around 7. I don't think you can safely have 3 kids pushing a cart together, especially one with heavy boxes on it. Of course, they were running, and ran right into the other cart from the side. Fortunatly, no one was hurt, but just like kids running under boxes, allowing them to push the carts is not a smart idea either.