Whenever there is a grounding, whether it is soft or hard, the boat should be pulled and inspected. I'll share with you two 'soft-grounding' stories.
1) A friend of mine is end running a marked sand bar. On the backside, it's a narrow unforgiving channel. Boats get impatient and start to run 2 -3 wide and push traffic out of the channel. You also need to follow the greens. If you follow the reds you cut a corner. My buddy softly goes aground in sand. Since it's a steep bank, he is able to reverse off of the bank and continue on his way. Since it was a soft "hissss" and no bangs or clunks, he thinks nothing of it. He has an Ipland Gypsy with a full protected prop and rudder with a sand shoe.
Leter that fall he hauls the boat. There was a rock or block (there used to be an old bridge in the area that was blown out in the hurricane of 1938. He ground his keel into the rock. This caused his keel to start absorbing water for the rest of the season. By the time he hauled it was too late. That winter he ended with massive reconstruction of his keel.
2) I was going down a river that has a narrow channel and also unforgiving (same river as the story above in a different spot). The area I'm in is full of rocks. The day mark is missing and I'm not paying attention. I go on the wrong side of where the day mark used to be. I hear a weird 'knock'. Just as I say "What was that noise", I slide to a stop. Prop is still spinning at 1,000 rpm, but I'm not moving. I kissed a rock on the way in, then found the only bit of sand/mud in that section of the river.
A marina neighbor passes by and gives me a soft tug. I proceed to the marina and have the boat hauled. There is a 1/2" knick in the Bronze prop. Shaft looks good when spen. No damage. I re-launch and spend the rest of the summer blissfully unaware.
That fall when the boat is hauled, I decide to have the knick in the prop fixed and the prop trued. While we're at it, I need a new dripless and I need to replace the cutlass bearing. Might as well send the shaft to be checked while we're at it.
Come to find out...The cutless bearing is trash, the shaft isn't true. It's borderline straightenable, but then they find the shaft key almost completely destroyed, the keyway wallowed out. To fix it, someone drilled and inserted two studs which were now acting like the 'new' shaft key.
Coupler, shaft, cutlass bearing and dripless all needed to be replaced. Now much of this was NOT a result of the soft grounding, however it did come to light as the result of it.
My opinion. ALWAYS haul and inspect after any grounding.
