Radiometric dating really irks young Earth creationists. They go to ridiculous lengths to try to prove that it's unreliable (by no less than about six orders of magnitude, which would be an astonishingly large error margin.) They do this by distorting the subject and outright lying about it.
One very common thing they do, especially when talking to other believers, is that they imply that there exists just one single form of radiometric dating, and that all datings are based solely on this single phenomenon. (Most often they do not mention any specific one, but sometimes they actually mention one of the element pairs that's used for this, potassium-argon being a popular one.)
They basically never acknowledge that there are, in fact, numerous different methods for radiometric dating, using different radioactive elements which have different half-lives.
It is often the case that a volcanic rock can, in fact, be dated using several different methods because they contain more than one radioactive material. This is a really wonderful thing with respect to dating such rocks because the more different methods can be used, the more accurate the estimation becomes. More importantly, if the different dating methods gave wildly different answers (such as one giving an age of 1 million years and another an age of 500 million years) it would be a good indication that there's something wrong.
Well, take a guess how well this works. It works wonderfully. When a volcanic rock containing several different radioactive elements are dated like this, all of them tend to give the same age for the rock, with very little variance (which is completely accounted for by the error margin, which is usually about 1%.)
Young Earth creationists cannot satisfactorily explain how the different dating methods could give the same age for such a rock. The arguments they present always deal with just one of such elements, not several.
For example, if material that's the result of the radioactive decay (such as argon or lead) were to somehow enter the rock (by an unknown mechanism) and make it look older than it really is, it would throw off one of the dating mechanisms but not the others, in which case they would give wildly different results. This doesn't happen. In order for this to happen all by-products would need to enter the rock in the right amounts for all the dating methods to coincide (since the half-lives of the elements are wildly different, the amount of by-product needed to make them coincide when dating would also be wildly different, and quite precise.) What exactly are the chances of this happening, every single time, everywhere?
Others claim that the radioactive decay can be accelerated by a natural phenomenon. (Of course they never actually point out exactly which natural phenomenon could accelerate radioactive decay by six orders of magnitude.) And again, it just doesn't work: This phenomenon would need to cause a different amount of acceleration on the decay of the different radioactive elements in order to keep them coinciding with each other (again because of their different half-lives.) This is just impossible, even if such a phenomenon existed.
But of course creationists love to ignore all this, and just stick with their own limited and fallacious arguments.