Isn't 500mA from a SOT23 regulator (?) a little optimistic... ? I'd derate to 100mA if I were you...
I don't think so. With a 4.5V input, you're talking a little over half a watt. Thermal resistance is 184C/W to ambient, so temperature could rise to 110C over ambient, so as long as ambient is below 40C, that's below the 150C max. Plus the regulator will shut down if you exceed the max.
Now, granted you wouldn't want to get anywhere near that temperature, but I went under the assumption that folks would want to know the peak current the regulator could deliver, not the continuous. It's unlikely anyone would be drawing 500mA from this tiny thing continuously.
Also, if I were a newbie and I saw a limit of 100mA, I would assume that was the peak current the regulator could deliver and I would be constantly worried about exceeding that, even briefly.