Given that there are seldom receipt records of tips, how can fairness be achieved for service workers during tax time?I worked in a service station...

Tips are taxable as income, regardless of whether or not
they are reported to the IRS by your employer.  For employers, the limit on reportable
tip income is $20.00 per month.  As a service station employee it is doubtful that you
would receive tips over the limit.  Nevertheless, any and all tips are reportable by
you, yourself.

The only way to assure fairness
is for you to keep a diary of your actual tips.  You should then add those tips to your
wages when you file your taxes.

Some restaurant
workers complain that their employer reports an average tip income for each employee,
whether or not a given employ receives that amount of tips.  The employees receiving
tips below the level reported by the employer are paying too much tax.  This would not
seem to apply to your situation.