Do you let your child wear training underwear or panties during toilet training age?

My friend is currently toilet-training her son and if they are at home, she'd just let him wear normal underwear so if accidents do happen, it's still not so bad. So far, so good, he has taken to potty training well. However, if they were out and about or at someone else's home like grandma's, she'd make him wear his training underwear just in case. However, he wears his normal underwear when he goes to daycare because I suppose the teachers are used to having kids who are being toilet-trained so if accidents happen, it's still not so bad.

My toddler is a boy. I let him wear underwear. Just normal underwear for him. I will bring him to the toilet every 30mins to let him pee .