[EarlsflyinCobra]

Okay, speaking as a 30 year + LEO I can say that some of the newer, younger, more zealous police officers I have observed tend to go overboard on some of their searches and their criteria for the searches. Yes, probable cause is needed for a search and sometimes when there is borderline (grey area) PC the subject is asked if they will consent to a search and then their reaction is observed to either strengthen or weaken the PC. Unfortunately there are officers out there that will really STRETCH the issue, thus reflecting POORLY on all officers.
I do not know much about the Coast Guard so I will limit my response to this on them; I am suprised they went so far as drilling holes without a lot of PC or Suspicion of Illegal Activity.
As far as the deputies following you into your drive for no license plate, I see no problem with that. However, after they questioned you and you supplied proof that it was a new vehicle (hopefully you had that) I do find it disturbing that they placed you in the back of the cruiser and searched your vehicle. to me this was a little much.

Now with that being said let me give a little of my perspective.....it is always easier to Monday Morning Quarterback these situations.....in the field it is sometimes harder to do......I was recently involved in case where a male subject committed a fairly serious, yet non-violent crime, a few minutes later I spotted a vehicle fitting the description of the suspect vehicle....in it was a male subject wearing clothes that fit the suspect description exactly....when I stopped the vehicle the subject was very cooperative and turned out to not only NOT be the suspect but be the nephew of a high ranking officer within my department....luckily through my EXPERIENCE and training I refrained from yanking the subject out of the car and searching it before I questioned the subject. There was a fairly new officer that was coming to back me up whom I have observed jump the gun on searches before and luckily he did not make it to the stop or circumstances could have been different.