In addition to the above and since you're using the ValidateRM plugin (hoorah!) you may want to also consider using $result->valid('userid') instead of $q->param('userid') to make sure you're taking advantage of all the goodes that ValidateRM provides.

If any of the params are using a filter (like trim or digit or a custom one) or if you eventually start using filters, doing this will stop you from having to change anything later. Filters are definately good to clean your data up.