I don't think, there would any problems, as it seems a matter of returning just address of memory space, either it be an huge data object, small integer value or null (no address).

Now what matter most is how understandable your code is. Our hardware is now too efficient that these things are meaningless now). My personal practice is to return anything when its make sense to return rather than returning 1 at end of each of function definition. (as it was often seen in C/C++).

I would think that it would be a bit slower!