Ditto, with a caveat- the one covered in part by rickair's last sentence:

There are cases in which a pilot has been violated on careless/reckless grounds for flying in the clouds in Class G airspace when the flight has a potential impact on aircraft in controlled airspace. Probably the most well known is Administrator v Murphy.

There's a good chance that in the arguments you've heard on this someone mentioned the case. Some people point to it as making all Class G IFR flight careless and reckless under 91.13(a) unless it is connected to an IFR flight plan; others read it as making Class G IFR flight careless and reckless under certain circumstances.