Perhaps we should get our facts correct. As a keen sailor I wouldn't expect to fill out a GAR (the 'A' standing for Aviation) but I follow the rules contained in Notice No. 8 - Sailing your pleasurecraft to and from the United Kingdom, which states that if sailing to a non-EU place (which the Channel Islands were when I last looked) I fill in a form (C1331 I think) and on return I have to phone number and sign and date the 2nd copy of my form. Whilst I appreciate that this is less than I have to do when flying , I have also been intercepted whilst underway by a Customs patrol boat, bit more difficult when you're flying !!