I've always heard squid came from Stupidly QUick, Instantly Dead.
I've not heard that version but I really do like it. I would also add this part from Urban Dictionary
"Back in the day before trackdays (an organized event to allow anyone with a motorcycle and the price of admission to gain familiarity with a racetrack and learn to ride faster, more safely than on the street) were common and new racers frequently had no track experience - hence their unpredictable behavior and unsteady lines led to them being labelled "squirrelly", as unpredictable surfers (or surfing conditions or surfing equipment) were also called." Leading to squirrelly kid then shortened to squid. Also heard it because of the flail that the squid makes flying from their motorcycle as limbs go everywhere.
My belief on a true squid is an inexperienced, unprepared rider. The rider often has a motorcycle that far exceeds their riding skill level (which really is a lot of us considering our bikes race design origins), often will use the bikes power for straight line acceleration but are seriously deficient in cornering/braking ability, minimal training if any at all, minimal or no gear (I consider absolute minimum helmet, you don't come back from brain damage), attitude of invincibility or recklessness, general overall unconcerned for their well being
I have 2 accidents under my belt, both in the first 2,000 miles of riding. The second one was even caught on film as I had a "Hold my GoPro and watch this" moment with my friend.
https://www.youtube.com/watch?v=mfaoOPJX1QE
I was wearing gloves, helmet, jacket, jeans and leather boots for both of them. Rode away from both (about 20 mph or less). Worst injury was a concussion from the first one. I've gone 9,000 miles in the last 5 months since, including the Advanced Rider Course and trip to the California canyons. I typically fully gear up for all rides of decent speed and/or challenging cornering.
I have started to squid out down here in AZ in other ways now. I have been riding with just my helmet, and gloves. Leaving jacket and leather boot/shoes at home. On days like yesterday I even ride to the local resort in swim shorts, trainers and t-shirt with helmet/gloves. The ride is about 3 miles and top posted speed is 45 mph. I follow Cambo's line of thinking in that it is a calculated risk, probably not the safest but also carrying your gear and trying to stow it at a resort pool just isn't practical. I don't feel that bad considering there are cruiser riders that rock their DOT bandana and CE approved sleeveless shirt for years, but then again, their skill level is appropriate for the type of riding they do.
I did meet a SoCal rider Nick who has started and pushed the NoSquidding movement. The whole message is safety and training. No judgment about the person who is squidding but rather a positive message to help encourage them to make better choices. Nick had a pretty serious off while Canyon riding in SoCal where he just had helmet and gloves on, he got lucky without any serious injuries but it was the wake up call he needed to wear full gear, and get better riding skill (for him it was the track).
No Squidding - Dress for the slide, not for the ride.
https://www.youtube.com/user/nickgnaime