I don't think so, theland. This seems to be a good idea. One thing I have noticed is how difficult it is for 14-18 year olds to get work. It is good for their confidence, experience, some independence, work ethic... but there is so much choice and competition for jobs, that it makes it difficult for them, even with unskilled, part-time jobs.
I think you have it the wrong way round, ich. Basic economics is demand and supply. The more competition there is for each post, the lower wages will go... so this may well give younger, semi-retired, people with young families, those with health or disability problems that can't work full-time, a better chance. Zero hours contracts are also a lifesaver for some people. They were for me as a single parent and I don't think removing choices, is really a way forward.