MROs are reluctant to take on work experience students because:
1. You will be non-productive for a good part of the two years
2. They will more than likely have to teach you hand skills
3. You will need to be 100% supervised
Due to these three facts, there is no gain for the MRO in offering you a work placement. In fact, it costs them money because the experienced engineer supervising you will take a lot longer to get the job done therefore productivity goes down and cost goes up. Those are the hard facts of it. They only gain for the MRO is the satisfaction of putting something back into the community by helping trainees.
Not in the best interest of our craft but in the USA conditions are much different. MRO's hire a percentage of people w/o any training or experience. As a supervisor/MGR we would rely and often direct our leads to train. You would start off removing and installing panels working often in bag bins. You would learn the basic standards for hardware/materials etc. If you were a quick learn you may assist a qualified person in changing parts, rigging and so on.
There is a benifit for the MRO to having you as they pay you usually half of what a liscenced person get's and all you have to do is what you are told withought the personal liability the AMT (liscenced) holds. Not to mention 100% buyback that is the catch all supposedly as a designated inspector is the final signature in US based MRO's.
I would be much happier to see no experience holding tech's going through this process as opposed to a farmer's kid who can make a few more dollars working in these operations with no desire to gain a liscence.