Personally, I have no problem complying with the Federal ban on these plants. There are so many other hygros that look just as good (or better) and they grow just as fast. These are all plentiful, available, and inexpensive. There's also a big variety of other fluffy, leafy, stem plants we can grow in clumps to add lots of color to a predominantly green aquascape. If we're not supposed to have this particular plant, okay.. no big deal. It's real easy for me to avoid this one by simply scratching it off my list. We already have such a huge variety of plants available to pick from no matter what tank conditions we're working with. It's not even possible to grow them all in one tank - the selections we have today are incredible.
I don't see any point trying to sneak certain plants here and there. Anyone looking at my tank who isn't knowledgeable about aquatic plants won't be impressed that I've chosen one species over another. They'll just admire, appreciate, or disregard the overall appearance based on how much they like it (or don't). But... Anyone who is knowledgeable about plants is going to take one look at my tank or photos I post of my tank and notice I've got an (illegal) polysperma in there. Fellow plant enthusiasts are going to think I'm either too stupid to know I'm growing a restricted plant... too careless to pay attention to serious environmental problems which prompt these bans in the first place... or too obstinant to follow very simple regulations on growing and transporting plants in this hobby.
I really enjoy having aquatic plants in my home and I value the natural environments around us. IMO, there's nothing to be gained by deliberately circumventing a Federal ban just to keep a single plant specimen.