From what I understand, when you shorten the cable, you change the impedance and so the signal is a bit attenuated. Nearly all installations are different. Some may experience problems. Some may not. It may work in the garage, but not when you're out on the water in certain conditions (e.g., certain depths, nearby structure). If you experience no problems in all your fishing situations, then your system is probably OK. It doesn't mean someone else will experience no problems too. That's why, generally speaking, many people say to not cut it.
2011 Hobie Outback (yellow)
2009 OK Prowler Trident 13 Angler (orange)