I have seen the kits to adapt the OEM lites to RV signal sourcing and accept that they work...But they use them things called diodes, which were not part of the curriculum in the 60's when I took the required 2 semesters of electrical engineering. I also do not like household wiring circuits with parallel switches and am very careful in wiring 230 volt circuits in Y or delta configuration.
A parallel boat trailer type toad liting circuit is very simple to understand and trouble shoot, esp under the gaze of a DPS trooper asking why the lites are not functioning. Mounting the additional bulbs/fixtures using magnets/removable brackets are reasonable workarounds.
To each his own solution