This is just a plain evil tactic, moving the cost of bad capacity planning from management, who made the decision, to the employee.
Same goes for it being extremely busy and calling someone who is off and asking if they wanted to come in to make some extra money.
He would always comment that the weather played a huge role in how busy they were, particularly a sudden downpour.
Planning around such ephemeral things is quite a challenge.
I own several retail stores. Labor is by far the largest manageable cost and whether or not we make any profit is often a direct result of managing our labor cost.
Re: being the one who should bear the risk, I am also the one who bears the responsibility to make sure they have a job tomorrow. If we don't make money then there is no job.
Of course, the alternative is that we could raise prices so that we don't have to be ruthlessly efficient. But then, the market doesn't tend to like that.
There are also other practices that people might be allowed to perform but which are prohibited - consider, for example, young children working for businesses outside the home. I don't think the willingness of labor is a reasonable metric to gauge the fairness of a business practice.
In general, I think it's the government's responsibility to make sure that pro-business positions (even understandable ones like what you're mentioning) don't unfairly hurt workers - to be fair, 'flexible' hours have been mentioned by the Obama administration multiple times this summer.
With all of the talk about raising the minimum wage drastically (small increments are fine), or something like requiring a certain minimum shift length, it will push small business owners towards non-human workers faster (automation and robots).
And a lot of us think the government should have nothing to do with regulating based on some vague notion of "fairness". As long as no one is being compelled to take any action, or make any choice, through coercive violence/force, the government - IMO - ought to stay out of it.
If someone scams your aging parents/grandparents into selling their house unfairly, do you think the government should stay out of it? After all, your parents/grandparents are the ones who willingly went ahead with the scam.
Do you consider monopolies a coercive force? If a local cable company (say, Comcast) holds a de facto monopoly over local internet, imposing high fees and bad service on customers, do you think the government should stay out of it? After all, no one is being compelled to buy internet; it's everyone's choice not to.
Do you consider monopolies a coercive force?
Not as a rule, no.
Doesn't make it OK. We're not machines. We're not robots. We're not fungible resource. We're people, and we object to creating a society in which the rich and powerful play off the less fortunate against each other, creating a race to the bottom until every employee is scratching out a bare existence in the knowledge that if they so much as ask for a five minute break they'll be fired and replaced with someone slightly more timid. Obviously the rich don't generally object to this.
But then, the market doesn't tend to like that.
Which is why we have government and unions. "The market" is meant to be a tool that serves people and makes life better. It's not perfect, it's not magic, and applied excessively it makes people miserable; there is very definitely a time to tell the religious caste in society that worships "the market" to get bent.
That's not an excuse. In early 20th century there were kids of 10-14 years old, "willing" to work in coal mines, as "breaker boys" (and other worse jobs).
https://www.google.com/search?q=breaker+boys&tbm=isch
Most advanced countries still outlawed it. You are only "chosing" to do a job if you're not directly pressed by starving or being homeless. When you can chose between job X or job Y.
When you're hard pressed to do whatever comes your way, you're not "willing", you're forced.
Scheduling is quite open to abuse from dodgy managers - for example, I had a friend who worked at a supermarket that rostered him on for 3.75 hours, then 30 minutes later, rostered him on for another 3.75 hours. This 'split shift' meant that they didn't have to give him the mandatory paid 30 minute lunch break for an 8-hour shift.
Same goes for it being extremely busy and calling someone who is off and asking if they wanted to come in to make some extra money.
This sounds like a balance, but it really isn't. "Would you agree to do more work" is not the opposite of "I'm reneging on our agreement for your current work" - the latter is unilateral.
Hospitality sucks. When I was in my early 20s, more than half the people I knew worked in hospitality. Now I'm 40, only one still remains in hospitality. It's an abusive industry that people get out of if they can - in general, it's short hours, odd shifts, bad pay, crap managers with little or no training, and no job security. Screw defending the practices of that industry.
Except they gave him 30 minutes between shifts? It sounds like all they did was schedule his lunch shift rather than letting him do it himself. My guess is that 30 minute break was at an inconvenient/non-rush time?