I have to wonder if the majority of people on this thread either don't stay in hotels, or have some super human toddlers.
Using a kettle?! You actually think a 2 year old will take the kettle out of a cupboard, take it to the bathroom and find a way of somehow using the adult-sized sink, then take it back to the room, plug it in and turn it on?
Yes, total risk there 
OP, I travel a lot and have never, ever stayed in a hotel that doesn't have a security chain or deadbolt on the inside of the door.
Also, the bathroom locks are the sort that can be turned with a coin. If you don't want her in there, shut the door, use a coin to turn the lock, bingo, she won't be going in.
If she is in an adjoining room with the door to the corridor locked from the inside and the door between your and her room propped open (except during romantic moments, she is at no greater risk than if she was in your room, but you get the extra space.
Honestly, I think some posters should be writing episodes of Casualty or CSI with their overactive imaginations.