Crew Contacts – Outports
• Crew on Reserve duties away from Home Base are to remain on call in the crew hotel unless specific instructions to the contrary have been issued by the Company.
• Crew not staying in Company provided accommodation shall leave a contact address and telephone number with the Company designated representative, as detailed in the crew briefing sheet, and the flight’s Commander/PIC. Crew are to take a responsible attitude towards their availability so that contact can be made within a reasonable time.
So as long as you are "staying" in the hotel, no problem. Check in, "stay" there, and show up on time, well rested, for your next duty. What you do for leisure inside or outside your hotel room is up to you. As for the last bit about being contactable, it's meaningless, since your rest period is time "free from duty" and you could be sleeping or skiing or drinking or boinking, you are not on reserve, and you do not have a free global roaming mobile phone provided by the company. I think a "reasonable time" to be contacted is when you are back in your room (if you wish) or when you are back on duty.
If they want you on duty by keeping you on reserve, then they should have to credit you for it. Why don't they credit you? Simple: People answer the phone and acknowledge crew direct for free.