Just a guess, but if SMB West thought there was a limitation there would be a "warning label" on the shifter or near the 4WD light or something...
Not that an absence of a label means there couldn't be issues - just that Alan's liability lawyer hasn't thought of that one yet.
Or maybe the warning label factory is running low on ink trying to keep up with governmental regulations.
Tough to really lay odds on which is more likely these days...
Remember: always wear your seatbelt, don't sit too close to the airbag, don't txt, don't talk on the phone, don't eat, and don't talk to your passengers. Especially when driving at highway speeds with 4WD engaged. Oh, and always latch the penthouse top.