One of the features of modern times, in my opinion, is the proliferation of instructions and an accompanying fear in novices of getting things wrong. Perhaps it has always seemed thus, but the media nowadays strikes me as particularly strong on nannying didacticism.
So, as reassurance, I can reveal that a member of my family, well advanced in years (no, not me!) has managed to go through life without ever knowing exactly how to harvest rhubarb. Both she and the rhubarb plants that have endured her cutting, rather than pulling, have survived, so it just goes to show that getting things wrong isn't as disastrous as we are sometimes led to believe.
However, harvesting rhubarb stalks by pulling is, according to Tom Cole in the Videojug production below, beneficial to the plant as it stimulates the roots. For best results in future years, you should also restrict your harvesting to plants three years old or more. Actually, he says you can harvest a couple of sticks from two-year-old plants, but only in the first two weeks, so it barely seems worth it.
So, just to stop you having to carry a sharp blade across the uneven surface of the garden (risk assessment - another feature of modern times), here's how to harvest rhubarb: