Unfortunately garden centers are permitted to sell some invasive plants (Tier 2 species on the linked list that the MD Dept. of Ag. generates) and as you noted, Rugosa Rose can be invasive in Maryland, though primarily only in coastal plain habitats. While your county does fit this habitat requirement, no records exist yet of the plant having colonized natural areas. Still, it's a risk that we would suggest not taking. Although containers might reduce their vegetative spread (ability to send up new shoots from running roots), the plant might still be able to spread from seed (in the hips) as well, so it might be undesirable to grow them in either the ground or a pot. Are you able to return the plants? If not, you could at least trim off spent flowers or immature hips (the seed pods) before they ripen and disperse seed eaten by wildlife. In that situation you won't necessarily need to keep them in containers but should monitor for any suckers (root sprouts)  as they mature so those can be trimmed back as needed to keep the plant in bounds and on the property.

Miri