I am not saying that these are the only options - it is just that these are often amongst the options that are proposed by the anti-smackers as alternatives.
My take on it is that it is just evidence that there are a range of possible parenting techniques - some of which other parents may not find acceptable. And that includes "time out", "going to bed without supper", "being given a talking to", "being ignored", "leaving them to cry". They are all just techniques. Some of which work with some kids and some families and some of which don't.
I used the "rope" trick (from Toddler Taming)on ds when he was making the transition from cot to bed, to stop him getting in the habit of coming through to our bed at earlier and earlier times. Some parents hate the idea of a child effectively being locked into their room. But it worked for us.
For the record - I came from a family where both mum and dad did very occasionally smack us (and who still agree with the principle) - but we are still close to our parents. My main memory of a punshment threat was of being threatened wit h my mouth being washed out with soap for "using bad words" .
And 30 years ago, my mother was unusual in being a teacher who didn't (and wouldn't) use the belt (Scottish corporal punishment), and yet was known for good discipline in her classes.