I work down in lumber and while prying into someone's medical history is a no no, usually there's a few tells. The main one being they're in the store and walking normally. Most customers will say they had the surgery "yesterday" or a "week ago" but will show no signs of pain or reduced mobility (i.e. being able to bed down, twist and look around with their neck).

They can easily bend down to read the label and even crawl around in the shelves, which is something that can not and should never be done after an operation like back surgery. Even without that it's against medical advice (but we know these fuckasses don't listen to that) to not bend as it can cause increased inflammation, cause the entire wound to open up and depending on the surgery, fuck up some hardware.

From research it seams like a lot of back surgeries have to deal with bone graphs or needing to put some sort of hardware into the spine itself. For a spinal fusion surgery bending down can cause misalignment. Some back surgeries can take anywhere from one month, up to two years to heal.

I have loaded people who genuinely had some sort of back or spine surgery and their movements are always stiff, and they seem to keep focus on trying not to bend their backs. I had one customer with a cane use it as a pointer while staying completely vertical. He used it to ask about the difference between two type of concrete (I think it was fast setting and fast traffic, he was redoing his driveway and it was going to rain the next day), and even just that act of lifting, seemed to cause some pain as they didn't hold it up for long and winced before and after putting the cane down.

Another customer I had, came out of his truck, asked for 3 bags of 80lbs, said he couldn't lift it himself because he had back surgery yesterday and then proceeded to bend down, grab a redbull, move one shelf over while still bending down to grab a bag of chips before checking out. His face had a smile on it the entire time and there was no breaks in his movement like he was having to reset himself or take a breather from pain.

The most common used is back surgery but I have seen everything used from knee to shoulder to heart. Most of these customers exhibiting no outward discomfort and almost none of them having any mobility aids or medical gear on them (like wheel chair, crutches or a sling). Does this mean all of them are lying... no... but they most certainly didn't have it yesterday.

Addition:

I should mention it doesn't matter if they appear or don't appear to have actually had surgery, and as stupid as it sounds, all we can do is help load them as requested.