Is it legal to show flags at house gate/on the car?

[tango42]

One guy has been doing it for years on his car.

Car Driving Around with Huge Chinese Flags blasting music

Today I was walking on ZhongXiao street and I hear this car blasting music from afar. As it comes closer it is flying a bunch of huge Chinese flags and has some signs that say China…something( Can’t read chinese). Is this really tolerated here? Has anyone seen this before? I mean s*** if I go to China flying R.O.C. flags would it be A okay?