Don't worry about it but it would be "bad practice" to bundle or zip-tie them tightly together, or to run them in the same conduit. If there was a problem you'd hear AC hum when the cables are close and it would go-away when they are separated.
Balanced connections are highly-immune to this kind of noise pick-up/interference, and they are also highly-immune to ground-loop hum, which is a more common issue.
Normal RCA audio cables are shielded (as are balanced cables) and line-outputs are low-impedance (as are balanced outputs) and both of those things help to minimize noise pick-up. The input is high-impedance so there is more chance of noise if the other end isn't plugged-into anything. Unbalanced connections are more sensitive to ground loop noise and if you get hum it's usually a ground loop.
If you have a turntable, the cables are also shielded but the phono cartridge is higher impedance which makes it more sensitive to noise, it also has a coil which is "good" for picking-up hum (but it is shielded too), and then the weak signal (and any noise) is amplified by about 1000 so the wires from a turntable should be more-carefully separated from power cables.
