I'm not sure that the Ace guy's knowledge base was particularly solid.....

Unless your patch is on the roof of an old warehouse in Pittsburgh, there will be rabbits in Zone 6 PA. And worse yet, groundhogs. It doesn't take "many" rabbits to be a problem. And it only takes one groundhog.

We live in a similar area, and we not only fence, but we trench to bury some outfacing angled fencing belowground to discourage tunneling. And we carry a finer mesh fencing up about 2 ft to back up the more open upper fencing..... I swear those rabbits just pass the babies through to pass out the groceries without that finer mesh low.

The blowing of the straw just adds another reason why.
Putting up fencing is not cheap, and there are other ways to manage if it can't be afforded, but if you can, I would fence. May save many kinds of frustrations later.

I spread a lot of straw in my garden/yard. We never have it blow. After we spread it, we lightly sprinkle with water to help settle it.

Even during wild thunderstorm, my straw doesn't move.

We also have fencing that does NOTHING to slow the bunnies down. Spraying with a homemade mix of two raw eggs, a drop of dish soap and water to make a quart (swirl in the blender) helps deter the rabbits. They hate the smell of raw eggs.

Dinner last night with a bunch of people centered around alot of gardening stories. The contractor guy who does alot of work around his property as well as for his clients said that the straw wont blow if it's wet. So there is a consensus.

I dont think I'm putting up a fence just yet.....I'm certainly going to soak that straw though, once it layed.