In the 90s in my first business I did support at home for people who thought they could get unpaid support from their friends, neighbours and neighbourhood kids. We were expensive and never lacked clients who had gotten unpaid support which had only made things worse.
The solution to the halting problem is to stop building universal/Turing-complete machines.
Edit: since this was downvoted, I will elaborate. The halting problem only applies to arbitrary programs on Turing-complete systems. It is possible to create useful systems that are not Turing complete. As a baseline example, it is easy to tell that the following Ruby program halts:
exit
Problems arise when one allows unbounded loops and unbounded recursion. If all loops and all recursions are provably finite, then a program can be proven to exit. All sorts of useful things can be done with systems composed of small, provably terminating programs. And it turns out, the vast majority (if not all) of the things relevant to securing a computer system can be implemented in formally provable ways.
I've found that people keep repeating this but it doesn't work. So a couple of places in our office have permanent marker marks with smudges all around it from where someone tried to wipe it off with alcohol then a dry-erase marker.
I've found the opposite, IME; perhaps the issue is with your boards? We regularly have this happen at work and the permanent marker is always removed. It also works on plastic containers - I've successfully done this hundreds of times on both reusable plastic bins for my food at work, as well as items I buy (and resell) from Goodwills and Savers / Value Villages. I've not yet run across a plastic container that this hasn't worked on.
I've obviously not tried this with "hundreds" of whiteboards, but the one we have on the fridge at home works as well as the several size and types we have at work.
Drawing over permanent marker with a white board marker does work provided the permanent marker hasn't dried yet.
Or, at least, I have done this successfully before now - so my current working assumption is "people are waiting too long after which it doesn't work", but since I like my white boards I'm unwilling to run the necessary experiments to test this.
I don't think time has anything to do with it. Rather it's the solvent in the dry erase marker. I used to use dry erase markers to remove extension numbers from the little tabs on 66 blocks back in the days before IP phones. Sometimes those numbers had been there for 15+ years.
So, my advice would be: if one brand of dry erase marker doesn't remove your permanent marker mark, try a different brand. I think I used Expo.
For the paywalls on many articles that I'm interested in I just Google search them. Many allow you to read the full article if you referrer is google.com