I started working with a local web design company and they sent us the first template of the design. The design is very nice and everyone in the company agrees that it's a lot better than what we have currently.

But one of the things I noticed is that they reuse (a lot) of the ids on the same page (opposed to have them as classes). When I asked them about this, they said they found that ids were more consistent when viewed in browsers and that many modern browsers won't care about multiple uses of ids and will render them fine. If javascript issue comes up, they will just create unique ids for them. And in the browsers I looked in (IE6, IE7, Safari, FireFox 1.5 and FireFox 2.0) they do show up fine.

Is this really an issue that I should pursue to have them fix it? It does seem a bit silly to complain if it does work fine for everyone.