Any one can leave a review on tripadvisor, even if you have not been to the hotel or restaurant. Now that's wrong.
Now this is what i would to to stop malicious and un true reports.
On the receipt from hotel / restaurant there needs to be a pin number which can only be used once... When keyed into trip-advisor that number brings up your details, like the day of visit, where you stayed and what you had to eat that day.
Then it tick boxes for quality, cleanness, value, services and so on. A bit like you have now but more detailed..If there is a problem with a business a report box with a yes or no button. Which is on screen for people to see. Then they can make up there own minds if the review is true or not.
With a final box for any other comments. no more than 50 characters. keeping it short and brief and to the point.
To HELP pay for these changes a very small charge could be made of $2.00 to all hotels and restaurants and who are on trip advisor site. Being a very small charge most business would pay as it's a small amount and the feedback is from honest customers who have visited your establishment / business.
UNTIL this happens tripadvisor can no be taken seriously..
All your review relay on honesty and to day people are not honest.