Immigration Site

What happens if a person applies for a non-immigrant visa (like visitor or student F-1 visa) during the waiting time of the Visa Number.
I know that if the beneficiary shows INTENT to immigrate to the USA permanently then he cannot be eligible for student visa...for example.

When can she/he still aplly for non-immigrant visas???

1) before being aproved by USCIS of the I-130 petition?
2) before the NVC receives documents like the DS-230?
3) before the interview at the consulate?

I ask because waiting times are so long that maybe the beneficiary wants to either travel or study in the USA while waiting for his petition.

After I-130 being submitted, consulate most probably wont issue non-immigrant visa unless its H1/L1.

But I thoguth that the INTENT to immigrate to the USA had to be shown by the beneficiary, not the petitioner/sponsor. In other words, if I submit a I-130 form for some family member, I dont think that shows that my family member (beneficiary) "intents" to immigrate to the USA.
So, while he/she waits for the Visa number, coudlnt he/she come to the US on a student visa?.

I thougth intent would be shown for example by filling form DS-230 with the NVC. There, the beneficiary signs that he/she intents to immigrate permanentely.

Is this how it works. Or once the I-130 is filed, there is no chance to get a non-immigrant visa??

Even though that is not your own petition, it is considered you are potential immigrant. It might be precise to describe that they wont issue non-immigrant visa to potential condidate of immigration.(A lot of F, J, B visa are rejected at consulate even though they do not have any immigration application being processed. Rejection is simply based on the thought that they might be potential immigrant)

On family base, I-130 is applied by relatives, but still considered that you have immigration intent.
On employment base, I-140 is applied by employer, but still considered that employee has immigration intent.