If you answer your phone, texts or emails when not available, or fully booked you run the risk of some guys trying to persuade, or hassle you into seeing them.
On the other hand I can often be busy during my working hours, and I do take a lot of advance bookings so where appropriate I will sometimes have my phone with me out of hours, or on days off. I won't put up with any hassle though, and have learned to be straight to the point. In the last two weeks I've had several guys phone me at short notice, late at night, offering me extra money to see them - I made it quite clear that a bit of extra cash isn't going to make my tiredness go away, nor persuade me to be lax in my security checks/screening - besides they also sounded rather 'dopey' themselves which suggested they'd been drinking. So it all depends on how you work, how you handle it and what you do in your time off. If I'm sat at home answering emails I see no problem in also answering a few phone calls. Sat in the car as a passenger I'll answer the odd text enquiry. At the cinema or on a night/day out with friends, phone definitely off.