Is a woman buying flowers, a get well card and $100 giftcard suspicious?
Could it be the couple buying $200 worth
of groceries and 4 $50 gas cards?
of groceries and 4 $50 gas cards?
Or maybe just the guy who decided
to buy 3 $100 giftcards?
to buy 3 $100 giftcards?
Who is a suspicious person in these scenarios?
Can you pick them out?

how they wear their hair?
By the hat, or maybe by their race?
How do you explain why you suspect a person?
Define suspicious::
tending to cause or excite suspicion: Suspicious Behavior

Define Behavior::
observable activity in a person or animal.
So this tells me they must act, before I can observe any suspicious activity; like, maybe they ask to pay for each item separately. Maybe the first card doesn't work, but the second does.
Long story short,
At work I got in trouble because I asked a lady for her ID when she was buying
2 $100 giftcards and paying with a credit card; she threw a fit!
Since than I've been told to only look at IDs of Suspicious people.
I asked what Suspicious looks like and they say,
"You know, Suspicious!" and walk away.
It just looks bad to ask for ID after he/she's swipe 2 cards and it works, but transaction #2 does not
work. That's when I involved a manager and it's up to them to give the card, ask for ID,
or keep the card and call the cops.
It's not my job!
Either make a policy and keep it
or don't do anything,
But most importantly
Don't Blame ME.
I'm just doing my job by what my managers say.