I don't know if you've already been on your trip but yes it is guest friendly. Have stayed there on 2 trips. Sometimes they ask for the girls ID but not always. They usually call your room when she is leaving as well.
I really like this hotel and its now my top choice in BKK. Rooms are not massive but are very modern and clean. Staff are always very friendly. Rooftop bar upstairs is reasonably priced and a great place to chill out. One of the best things about this hotel is that Soi 2 is really quiet at night in comparison to Soi 4, yet is only a couple minutes walk away (unless you're dodging the ladyboys at the Rajah! :P). When checking out on my first stay, they gave a card for 10% discount for return customers if you book through their website. Works out considerably cheaper than booking through Agoda etc.
Have a good trip!