They haven’t with Playtime. My battery switch, in the negative line, is a detachable (when switched off) metal handle, with no colour or other marking.

After owning 3 previous boats, all with battery switches in the positive (non ‘earth’) side, I was surprised when I discovered that Playtime switched the negative line. However, on thinking about it, I could not actually see any problem with the arrangement and it means there is only 1 switch for both batteries, rather than 2 or a 1 – 2 – Both switch.