What happens if there are many 120 ohms resistors as terminators on the CAN bus?
Assuming that the data receivers are capable of working with the smaller signal (which I'm sure they are), the only aspect that might cause problems are signal reflections.

Given that data rate is 19,600 bps, if you said this was a square wave of frequency 10 kHz, I'd be considering the wavelength of the 7th harmonic in order to justify that the cable length was OK.

7th harmonic is 70 kHz and this has a wavelength of 4.3 km. General rule of thumb is that a badly terminated cable will be OK if the length of the cable is below one-tenth of the highest wavelength and clearly it is.

Further reading: Why does the CAN bus use a 120 ohm resistor as the terminating resistor and not any other value?