There are at home test kits one can get to verify HLVd, watch the price I found one @ $21 but minimum 10 kits most do not give up front prices (kinda scary). Also in lab testing which I am sure is costly.
That plant in the vid above with the big ass knot, I would have to cut open to see there is no bug/worm in it.
Reviewing the info, I think I have had 2 plants with HLVd, one had twisted leaves and limbs, the other had 2 distinct types of growth with part of it stunted and part looked normal. Both were from seed with one showing signs early on, the other a bit later and split into 13 directions at its top. The first was pulled and burned (in a fire pit), the second was just not worth lighting up and was sent to compost (now I would also burn it in the pit). At that time I was using water from the spring, now I use water from the hose which may help get rid of this viroid because of the chlorine/chloramine in it.
I also found some articles that contradicted each other as to whether seeds can carry HLVd, one said no the other said about 8% can.