"No protein/only eggs" should be an option, but the extra cost probably can't be helped. If they can buy meat sausage in bulk at a lower rate, that savings can be passed on to the customer. If their plant based sausage can't be bought in bulk or doesn't come with the same savings to do so, then that cost must be factored into the product to maintain margins.
vegetarian
Stuff like this is infuriating. Yes there are people who cannot imagine not eating meat, my father is one of them… but he also admits he only eats meat once a week at most.
How about some of that tasty "plant egg"?
Maybe they ment to say egg plant but got the word order mixed up.
Maybe they used creosote eggs? When I was a kid my best friend's older brother told me they were rabbit eggs.

I always have to chuckle about how the protein myth is just now so very pervasive that I can order from Qdoba, and it prominently says "no protein" on it, even though it's filled with rice and beans and wrapped in a tortilla....heck even the guac in their own nutrition chart has a bit of protein in it. But, nope, in a lot of peoples' minds, only charred dead flesh = "protein".
These checkout options and labeling by restaurants is doing very little to correct the myth, that's for sure...