Tbh there are ways of pulling off a loadout with an eye for detail and a bit of research with out ever having to wear any insignias, ranks or berets and possibly offending people.
If you look closely you can identify units sometimes just by the kit they wear.
these are only rough outlines for example:
If you are doing a typical para dpm loadout use a para helmet instead of a mk6
Afghan loadouts are even easier.
Early 2 para wore ddpm trousers and top, mk2 osprey with standard plce webbing over the top plus a para helmet.
Early 3 para wore ddpm trousers, ddpm ubacs with ddpm blackhawk plate carrier plus para helmet ( most with choc chip helmet netting).
Early royal marines wore ddpm trousers, dpm shirt/jacket with either dpm plce or dpm assault vest
Later marines wore ddpm trousers, ddpm ubacs but then dye the ubacs green and wore mk2 osprey.
The list goes on but I'm sure you see what I'm getting at.
So some people will recognise the load out without the need for patches.
Just to clarify I did for 1 photo in the pictures section but was for reference of a loadout, but would never airsoft with them.