Something that I don't believe anyone has mentioned in this thread is that Navionics actually gives you the ability to update your own chart so you have the ability (and I dare say RESPONSIBILITY) to update the chart so that others (and even yourself when you return to that spot) can have the most updated data.
Think about the nature of the ocean (and even lakes)... water in general. It's constantly moving and changing, thus changing the land around it and under it. These changes make it impossible for any company or organization to have all charts correct in all places at all times.
I was sailing in the Caribbean and there is a bank of moving sand that was slightly off on my Navionics chart and I ran aground. When the locals helped me off they told me that area was known to the locals for it's shifting sands. Instead of posting on a forum to complain about it or contacting Navionics for a whining session I took responsibility (using the tools that Navionics has given us) and I used Community Edits to update my chart and share the data with everyone else that utilizes Navionics.
Community Edits allows users like you and me to simply click on the point of interest, click the question mark, click Edit Map and enter information about that spot. Once you connect to Wifi or cell signal that data is uploaded to the Navionics servers where it is reviewed and then uploaded to the rest of the Navionics community so that all of your fellow boaters can benefit from your experience.
I realize that we pay money to these companies to give us the best data possible and help keep us safe on the water but no company has enough manpower to cover every nook and crannie of the entire globe. Instead they give us the ability to help ourselves. So let's help ourselves.
