Can I ask people attending my wedding to pay?

Getting married mid next year and sending out the RSVP’s soon. I wanted to include in it no gifts and ask that if possible guest pay $30 each when they return the RSVP. I live in NZ so obviously NZD.
I’ve already put down the deposit on my venue and this money would cover their meal from the caterer I’ve been looking at.
I’ve never seen someone do this and it might be a dick move, but getting married on a budget is what it is.

For those of you who don’t know, it’s not common practice in New Zealand for parents to help with wedding payments. They might a little bit with the brides dress or things like that, but they don’t help pay for the actual wedding.
Can I ask people attending my wedding to pay?
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