I've done something similar, except I tried to scare them with a vacuum cleaner. I've also heard of putting them on the washing machine while it's running.
Whichever way you do it, they'll need to be in a box or carrier together. I feel more comfortable with a box. It lets me get to them faster if one gets aggressive. You'll also need one person to drive and one to handle the bunnies.
A lot of rabbit rescues have had good luck with this method, when used with the other normal bonding methods. I did not have luck doing this, but that pair didn't do well in the bathtub either. The standard advice didn't work much for them, although it is helping me with rebonding two sisters right now.