@ Jack
I suspect the only time the two plugins would actually conflict is if they were both on the same page. Or, if their widget and directory were on the same page. Otherwise it should be fine.
I was looking at their code… the problem I see with their solution is I register my Google Maps PIA instance as a dependency so when they unregister my instance they also inadvertently unregister all the scripts which depend on it. Well, more accurately WordPress not enqueue the other scripts because the dependency is missing.
Unfortunately the only solution seems to be to ignore the error message from Maps marker.
I might add the option to check for dependencies and ensure that they exist and if they do not, re-register them … it’s kind of like an arms race solution, not ideal at all. :(
