I haven't looked through 100% of the topics for these challenges, but from what I've seen so far, everything was done w/ MS paint alone (with mouse), drawing, coloring, etc. I suppose there could be a different challenge all together if people want to show their talent on a tablet. I think it would be awesome to see what others can do w/ those things. Ya, it might hurt the number of entries on here, but there was never an issue regarding tablets until the last few posts because everyone just used their mouse. I still see some awesome entries done w/ mouse alone.
Technically, the rules DO state "MS Paint only" which, in my opinion, that means no help from outside sources/items. But hey, that's just me.