I believe you guys got lucky and it depends on the State, region, management, etc.
Most of the time they will not refund shipping fees even if it is their fault for not properly checking the instrument before putting it up for sale. Their return policy does not cover the defective product scenario, so they just generalize:
If you’re not satisfied, neither are we. If for any reason you’re not completely satisfied with your purchase, simply return it in its original condition within the return period and we’ll give you a full refund of the purchase price, excluding shipping and handling charges.
Not long ago, I had an awful experience at the Orlando, FL store because they did not refund the shipping even if the bass was defective. I had to call the 800 number to get the shipping fee back.
Next day, I talked to the district manager to complain about the store manager "I don't care" attitude as well.
The DM did agree that defective product refunds should include shipping, and he said he would be discussing it with the store manager.