I don't know of hotels that prohibit visitors, but some charge a "joiner fee", even if you paid for double occupancy, to bring a local to your room.
I had hundreds of boys to my rooms mostly in Thailand, and some Cambodia, Myanmar, Vietnam, Taiwan, Brazil as well, and never had a problem. I stay at places that would be classed as 1 to 3 stars.
If you ride the taxi with boy together, 15 or 20 min should be no problem. If you want the boy from online dating to come to your place, some may balk or ask you to send money for taxi by online banking, and some will keep the money and not show up.