Detect if write queries are possible and show an ugly warning message

[simonw]

https://twitter.com/getluky/status/1424941270221266946

These are all great recommendations and would definitely help! Even better would be if the tool could programmatically detect or warn of unsafe configurations...

[simonw]

One way this could work is to attempt a harmless UPDATE against a small table - maybe one created specially for that purpose. If no error, either show a warning or disable the tool entirely.