I would say most websites with a somewhat thought-through graphical design use social media icons (i.e twitter, facebook, youtube, et.c) which are altered to fit the theme and design of the site.

Now, my boss insist we only use the ones provided by say facebook or twitter themselfes (in fear of getting sued or lose credability), but sometimes it just doesnt look very good on the site.

What is the common practice for these things? What do you risk by using an altered logo? What should I tell my boss?

I'll provide a few examples, what'd happen if I put any of these on a site?