Many programs have a set of default settings that are enabled if the user does not make any other selection. These default settings are not necessarily physically valid; instead, they are intended to produce syntactically complete input files. A prominent example of this practice is the weak-coupling thermostat method of Berendsen et al. , a profoundly important simulation algorithm that was routinely used for decades. Though useful and capable of quickly equilibrating a system at the desired temperature, it yields an ensemble of kinetic energies that is inconsistent with the expected canonical ensemble. As such, users should not rely on such algorithms, even if they remain available in the software and are often presented as a default choice.