I worked for one of the largest banks in Australia as a contractor. When I first joined, "we don't discriminate based on the employment type". The perm staff were wonderful in that regard. Then a new COO joined. He was a fucking sociopath. First we started getting locked out of various internal sites, needing to "reapply" for security reasons. Then they introduced the email badging that appended a big "(EXTERNAL!)" to your name in the address book. Then, if anyone attached anything to an email that included even one contractor as an addressee, they'd see a big WARNING! reminding them that they were potentially leaking the keys to the kingdom to us untrustworthy SOBs. Then in November a big rumour started going around that contractors were going to be "surprised" with a forced 6-week holiday (normal shutdown for contractors was 2 weeks over the break). I politely called out the COO directly on the internal Yammer, asking him to please put an end to the rumour mill and just confirm or deny whether it was true. I said the company would be within its rights to make that call but reminded him that "contractors are people too" and given the time of year, might want to know if their services weren't needed in January. I got a bunch of support from employees (and the managers I worked for) - perm and contractor alike. Many perms were embarassed and apologetic for this outcasting of contractors (way to increase morale Mr.COO). Anyway, within 24 hours, I was pulled out of a meeting and escorted out of the building. The entire Yammer forum was nuked from orbit (I still have a couple of screenshots) and I ended up in their non-existent "black book". I know this latter point because in the intervening years I would occasionally get pinged by recruiters for roles at that bank. I'd laugh and told them I was probably still in the black book and to contact so-and-so to confirm whether I'd be welcomed back. They were always surprised when they did so and were bluntly told that I was not welcome.

Since then I've been a perm at a couple of places were I had hiring responsibility and teams that included contractors and I ALWAYS made a point of treating them EXACTLY the same. I also never encountered another organisation that was as fucked in their treatment of contractors.