What are the disadvantages of radiant warmers?

Could you elaborate on the potential drawbacks of utilizing radiant warmers? Are there any specific concerns or issues that healthcare professionals should be aware of when considering their use, particularly in relation to patient safety, comfort, and potential for unintended consequences? Additionally, how do these disadvantages compare to the benefits that radiant warmers offer, and are there any alternative methods of maintaining body temperature that may be more suitable in certain situations?