Can you enter US for visit while applying for k1 visa?

I am looking for the answer to the same question!

According to things I've read, it seems it is legally to travel to the USA under the VWP (if applicable) but just for a 'holiday. It is advisable to take proof that you intend to return to your country after your holiday, i.e. proof of employment, bills, proof of address.

It appears to be legal but a gamble!