If this isn't a once in a life time, or once every few years kind of trip, then I think it's an appropriate consequence. Does he like to go to DL? If he doesn't, it's a rather useless consequence.
I think kids these days have such a sense of entitlement, that they deserve everything given to them. They don't truly comprehend the difference between a right and a privilege. They earn privileges. I think that when they don't do their jobs (staying away from drugs, applying themselves appropriately in school, etc.), then they need clear consequences, ie losing their privileges. Trips to
Disneyland, in my opinion, are privileges. Cel phones, internet, t.v., extra-curricular activities...all privileges.
I wouldn't cancel a Disney trip if I didn't have an appropriate alternative for one of the kids, but I wouldn't think twice about leaving one with family under the circumstances.
Edited to add.....all of the above is assuming that you think a punishment or withholding of privileges is appropriate. If you think he's troubled, depressed, or trying his hardest and just not doing well, dealing with something bigger, etc. something like that might not be appropriate.
