PCB power track width reduction for small signals?

Is it a good idea to reduce power track width (from for example 100mil) to say 12mil by using a 0R resistor in the schematic? On the power side I use net class 100mil, on the other side a net class of 20mil or something.

The problem is that power track needs to be wide, but track to electronic sensing circuitry does not need full power track width.

In the Eagle files attached this is visible by the use of 0R SMD resistors. Also in a current sensing circuit where a power resistor of 0.12R is used.

Any objections?

Thanks a lot for your comments,
Erik

Adding components seems an odd way of doing it?

Can't you just select track segments and change their width, or add branches in a narrower track??

I use autotracking so track section all have the same width. But you are right, much better way is to manually change the concerned track segment widths. Or maybe better in my case: still add this 0 Ohm resistor, get autotrack to use the small track width at the small signal side of the 0 Ohm and after autotrack is done manually replace the 0 Ohm resistor and short the two pads.

I was not sure how others would do this not realising most of you probably do not use the autotrack feature.

Found it: part SJ in jumper.lbr in standard library of Eagle