I use custom validation and a custom action after successful validation by using parameters : &eFormOnValidate=`checkSignup` &eFormOnBeforeMailSent=`doSignup`
I found out if I don’t do this in my &eFormOnBeforeMailSent function:
$fields['housenr'] = $_POST['housenr'];
$fields['zipcode'] = $_POST['zipcode'];
the integers will have added thousands seperators. I don’t primarily use eForm to email but to validate and insert into a table. The seperators however destroy perfectly valid integers. I think it’s a "bugfeature"

It makes for pretty formatting in emails and that’s what eForm it is designed for. But: can I toggle this behaviour for eForm2db style usage?