".... difficult and slow to start Vitis Riparia plants from seed"

Noxious weed is some areas, prohibited in Ohio. May be injurious to nearby trees and shrubs if not controlled.

It doesn't sound like scarifying would be especially helpful, or soaking either. They do need to be stratified, the chill must be moist to be helpful, dry storage in the refrigerator is only storage - the key is the moisture.

Plants for a future database: "Seed - best sown in a cold frame as soon as it is ripe. Six weeks cold stratification improves the germination rate, and so stored seed is best sown in a cold frame as soon as it is obtained. Germination should take place in the first spring, but sometimes takes another 12 months. Prick out the seedlings into individual pots when they are large enough to handle and grow them on in a cold frame for their first winter. Plant out in early summer."