Ask if they can pack it in oxygen. If not, you might consider replacing the air at times during the trip, and keep the water in the bag in gentle motion (the car may do that for you).
No - if it is too different, you need to match the receiving tank's salinity (assuming it is a QT with no fish in it). You can lower the salinity very easily during a short acclimation - says 1.025 to 1.020. However, going the other direction, low to high must be done in stages, and cannot be done properly in a bag or a drip tray. I never raise salinity (specific gravity) more than .003 units in 24 hours.
Just be sure he didn't mean 30 ppt! 1.030 is really high, the Red Sea is only 1.028. 30 ppt is equivalent to a specific gravity of 1.023 or so. You can probably acclimate from 1.023 to 1.025, but it is right on the boarder of too much to do at one time. Be sure to aerate during longer acclimations.
Ya I don't know he said he keeps it high because of this reason. He mentioned other lfs keep it at 1.021 or less so alot of fish die. So I assume he really meant 1.030.
I drip acclimated mine for an hour then put him in my quarantine with cupramine and 1.5mo the later he’s doing really well
