Formal and semiformal nights on Alaska cruise - need information!

[ClaireinTN]

We are contemplating one of DCL's Alaska cruises, and I am wondering how seriously people will be taking the recommended dress code for the formal and semiformal nights. I do not own anything that could be called a gown, and I have no desire to (own one or wear one for that matter); H feels similarly about tuxedos. We have never cruised DCL before but have cruised on several other cruise lines and generally we skip the dining room on formal nights, but I feel like we would be missing part of magic of the experience if we did room service for dinner those two nights on a Disney cruise.

So, my question is, will most people be in formal or semiformal wear? The closest I see us coming is a skirt, sweater, and sandals for me and khakis, a sport coat, and oxfords for H. Will we be considered spoilers of other peoples' dining experience in such attire?