While I would not fish using a ballon or cork attached to a line since it is illegal here I don't see your comparasion between hunting and fishing. In many areas hunters bait an area with corn or other feed or a salt lick to pull the deer to them. I don't see much difference in this practice than attaching a line to a crappie to find the location of other crappie.

The animal you hunt has no say in it's death since you shoot it from a distance.

A fish doesn't get caugth until it opens its mouth and takes the bait.

Nor do I see much difference in attaching a line to a fish to find their location or using a fish finder to find their location, other than the first method is illegal in the states i have fished.. Both are aftifical means to locate the fish. I have never attached a line to find the location of fish but I have used fish finders from the day I was able to afford to buy one.