No. That is super hostile to your users, and besides the use of + as recipient delimiter is a convention, not a standardised behaviour. You will get false posi

No. That is super hostile to your users, and besides the use of + as recipient delimiter is a convention, not a standardised behaviour. You will get false positives, and you will get irate users, often rejecting perhaps some of your most promising early adopters. See also: case sensitivity in the left-hand part of an address.